Coil manufacturing method and coil bending jig

Abstract

To provide a manufacturing method for a coil and a coil bending jig that make it possible to maintain the coil characteristics without reducing the alignment of a wire due to a bending process.SOLUTION: The manufacturing method for a coil includes a flat coil forming step for winding a conductor around a plurality of layers (or a plurality of rows and a plurality of layers) to form a flat coil with an empty core, a first heating step for heating the flat coil formed in the flat coil forming step to a predetermined temperature, a bending step for bending at least a part of the flat coil heated in the first heating step at a predetermined angle in a direction perpendicular to a surface of the flat coil, and a second heating step for heating the bent coil formed in the bending step at a predetermined temperature for a predetermined time.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a coil manufacturing method and a coil bending jig for manufacturing a hook-shaped coil in which a portion of a planar coil in which a conductor wire is wound in multiple layers (or multiple rows and multiple layers) is bent at a predetermined angle in a direction perpendicular to the surface of the planar coil. [Background technology]

[0002] Conventionally, as a method for manufacturing an irregularly shaped coil, for example, a hooked coil, a method has been generally used in which, as shown in FIG. 13, a round wire having a circular cross section or a square wire having a square cross section is used to form a planar coil 1A having a predetermined shape (for example, an oval or a substantially rectangular shape) wound in multiple layers (or multiple rows and multiple layers), and a part of the obtained planar coil 1A is bent in a vertical direction perpendicular to the planar coil portion 1a to form an L-shaped coil 1B.

[0003] Also, a coil manufacturing method has been proposed that includes a 90-degree bending process in which a winding (planar coil) formed in a winding process is bent (for example, Patent Document 1).

[0004] The coil manufacturing method described in Patent Document 1 involves bending the winding (planar coil) formed in the winding process by 90 degrees using a pair of bending dies. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-251995 Summary of the Invention [Problem to be solved by the invention]

[0006] However, as shown in Fig. 13, in the conventional method of forming a planar coil 1A with multiple windings (or multiple rows and multiple layers) and then bending a portion of the resulting planar coil 1A vertically to form an L-shape, there is a problem that the wire material shifts at the end of the bent portion (vertical portion) 1b (below the two-dot chain line in Fig. 13(B)), which negatively affects the coil characteristics, such as increasing the potential difference between the windings and affecting the structural assembly. In addition, there is a problem that the bent portion of the coil protrudes laterally, as shown in Fig. 14.

[0007] Furthermore, the coil manufacturing method described in Patent Document 1 has the problem that when bending a planar coil in a right-angle direction, a large stress is applied between the coil wires at the bent portion.In addition, there is also the problem that the copper core wire and the insulating coating layer on its surface have a large spring back, causing a larger return than the intended bending position.

[0008] In the conventional coil manufacturing method described above, the bending process causes deformation of the copper core wire, which distorts and refines the crystal grains, increasing resistance to deformation, increasing hardness, and decreasing elongation, resulting in the problem of large stresses occurring inside the coil wire at the bent portion. Furthermore, while annealed copper wire is typically the mainstream conductor material for coil winding, there are also wire materials that have undergone secondary or tertiary processing. These wire materials are subject to the above-mentioned problems due to the stress distortions that occur during secondary or tertiary processing.

[0009] SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a coil manufacturing method and a coil bending jig that can maintain the characteristics of the coil without reducing the degree of alignment of the wire rods due to bending.

[0010] Another object of the present invention is to provide a coil manufacturing method and a coil bending jig that can finish the coil dimensions with high precision after bending and can suppress stress between the coil wires and inside the wires at the bent portion. [Means for solving the problem]

[0011] According to the present invention, a coil manufacturing method includes a planar coil forming step of winding a conductive wire in multiple layers (or multiple rows and multiple layers) to form an air-core planar coil, a first heating step of heating the planar coil formed in the planar coil forming step to a predetermined temperature, a bending step of bending at least a portion of the planar coil heated in the first heating step at a predetermined angle in a direction perpendicular to the surface of the planar coil, and a second heating step of heating the bent coil formed in the bending step at a predetermined temperature for a predetermined time.

[0012] Conductive wire is wound in multiple layers (or multiple rows and multiple layers) and the formed planar coil is heated to a predetermined temperature. Then, in a bending process, a portion of the planar coil is bent at a predetermined angle in a direction perpendicular to the plane of the planar coil. The formed bent coil is then annealed by heating it at a predetermined temperature for a predetermined time, thereby maintaining the coil's characteristics without reducing the degree of alignment of the wire due to the bending process. Furthermore, by heating and annealing the bent coil after bending, there is no lateral protrusion in the bent portion of the coil, and stress between and within the coil wire is suppressed, thereby suppressing springback that occurs in the formed coil. This allows the coil dimensions to be finished with high precision after bending.

[0013] It is preferable that the method further includes a forming step in which the bent coil formed in the bending step is formed into a predetermined shape and dimensions using a forming jig, and a third heating step in which the bent coil formed in the forming step is heated at a predetermined temperature for a predetermined time.

[0014] In the bending step, it is preferable to press both sides of the bent portion with a presser jig and perform the bending process while repeatedly loosening and tightening the pressure on both sides of the bent portion.

[0015] The planar coil has a pair of parallel portions extending parallel to each other and a pair of connecting portions connecting the ends of the pair of parallel portions, and in the planar coil forming process using a wire material that is not a fused wire, it is preferable to wind only the pair of parallel portions of the planar coil while applying adhesive varnish to each layer.

[0016] Preferably, the conducting wire has a fusion layer on its surface, and in the first heating step, the planar coil is heated to a softening temperature of the fusion layer.

[0017] In the first heating step and the bending step, the heating and bending are preferably carried out in a plurality of different temperature zones.

[0018] In the planar coil forming step, when forming each layer of the planar coil, it is preferable to form the layers so that the predetermined dimensions are gradually reduced in the vertical direction at the end to be bent to form a step.

[0019] In the first heating step, the second heating step, and the third heating step, it is preferable to use a heating method in which the jig in which the flat coil or the bent coil is set is heated by high-frequency induction heating, and heat is conducted from the jig to the flat coil or the bent coil.

[0020] According to the present invention, the coil bending jig is a coil bending jig for manufacturing a hook-shaped coil in which a portion of a planar coil in which a conductor wire is wound in multiple layers (or multiple layers and multiple rows) is bent at a predetermined angle in a direction perpendicular to the surface of the planar coil, and is equipped with a pressing jig that presses down on both sides of the bent portion of the coil, and the pressing jig is configured to repeatedly loosen and tighten the pressure on both sides of the bent portion when performing the bending process.

[0021] The coil bending jig is equipped with a pressing jig that presses down on both sides of the bent portion of the coil. When bending, this pressing jig repeatedly loosens and tightens the pressure on both sides of the bent portion. This prevents the bent portion of the coil from protruding sideways (see Figure 14), as occurs in conventional manufacturing methods, and enables the coil dimensions to be finished with high precision after bending. [Effects of the Invention]

[0022] According to the coil manufacturing method of the present invention, a planar coil is heated to a predetermined temperature, and then a portion of the planar coil is bent at a predetermined angle in a direction perpendicular to the plane of the planar coil in a bending process. The resulting bent coil is then heated to a predetermined temperature and formed into a predetermined shape and dimensions using a forming jig, and then annealed by heating at a predetermined temperature for a predetermined time. In the planar coil forming process, when forming each layer of coil, the end to be bent is gradually reduced in size in the vertical direction to form a step. This allows the coil characteristics to be maintained without compromising the alignment of the wire due to the bending process. Furthermore, by forming into a predetermined shape and dimensions using a forming jig and then performing an annealing process, stress between and within the coil wire can be suppressed, thereby suppressing springback in the formed coil product, and the coil dimensions after bending can be finished with high precision.

[0023] The coil bending jig of the present invention is equipped with a pressure jig that presses down on both sides of the bent portion of the coil. The pressure jig is configured to repeatedly loosen and tighten the pressure on both sides of the bent portion when performing the bending process. This prevents the bent portion of the coil from protruding laterally (see Figure 14), as occurs in conventional manufacturing methods, and allows the coil dimensions to be finished with high precision after bending. [Brief explanation of the drawings]

[0024] [Figure 1] 3 is a flowchart showing steps for manufacturing a coil by the coil manufacturing method according to the first embodiment of the present invention. [Figure 2] 1 is a perspective view showing an example of a hook-shaped coil manufactured by a coil manufacturing method according to the present invention. FIG. [Figure 3] 1 is a cross-sectional view schematically showing a winding jig used in a planar coil forming step of a coil manufacturing method according to the present invention and the formed planar coil. FIG. [Figure 4] 1 is a perspective view showing an example of a coil bending jig used in a bending step of a coil manufacturing method according to the present invention and a bent state of the coil. FIG. [Figure 5]10A and 10B are a plan view and a side view schematically showing another configuration example of a coil bending jig according to the present invention. [Figure 6] 1 is a cross-sectional view showing a coil obtained in a bending step of a coil manufacturing method according to the present invention. [Figure 7] 10 is a flowchart showing steps for manufacturing a coil by a coil manufacturing method according to a second embodiment of the present invention. [Figure 8] 1 is a perspective view showing an example of a forming jig used in a forming step of a coil manufacturing method according to the present invention. FIG. [Figure 9] 10 is a perspective view showing a state in which the coil obtained in the bending step is placed on a forming jig and pressed and formed in the forming step. FIG. [Figure 10] FIG. 10 is a perspective view showing a state in which a jig for pressing the side surface of the coil is attached in a molding process. [Figure 11] FIG. 10 is a perspective view showing a state in which a jig is attached to hold down the hooked bent end portion of the coil in the forming process. [Figure 12] 1 is a perspective view showing an example of a hook-shaped coil manufactured by a coil manufacturing method according to the present invention. FIG. [Figure 13] 1A and 1B are cross-sectional views showing a schematic diagram of a conventional coil manufacturing method, in which (A) is a planar coil formed in a planar coil forming process, and (B) is a hook-shaped coil obtained in a bending process. [Figure 14] 10A and 10B are diagrams showing the state of a bent portion of a hooked coil manufactured by a conventional coil manufacturing method. DETAILED DESCRIPTION OF THE INVENTION

[0025] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a coil manufacturing method and a coil bending jig according to the present invention will be described with reference to the drawings.

[0026] FIG. 1 shows the steps of manufacturing a hooked coil using a coil manufacturing method according to a first embodiment of the present invention. FIG. 2 shows a coil 100 manufactured using the coil manufacturing method of the present invention. FIG. 3 shows a winding jig used in the planar coil forming step and the formed planar coil, with (A) being a cross-section of the winding jig and (B) being a cross-section of the planar coil. FIG. 4 shows an example of a coil bending jig used in the bending step and the bent state of the coil. FIG. 5 shows another example of the configuration of a coil bending jig used in the bending step. FIG. 6 is a cross-section of the coil 100 obtained in the bending step.

[0027] As shown in FIG. 1, the coil manufacturing method according to the first embodiment of the present invention includes a planar coil forming process (step S1) in which a conductor wire is wound in multiple layers (or multiple rows and multiple layers) to form an air-core planar coil, a first heating process (step S2) in which the planar coil formed in the planar coil forming process is heated to a predetermined temperature, a bending process (step S3) in which at least a portion of the planar coil heated in the first heating process is bent at a predetermined angle in a direction perpendicular to the surface of the planar coil, a second heating process (step S4) in which the bent coil formed in the bending process is heated at a predetermined temperature for a predetermined time, a cooling process (step S5) in which the bent coil is cooled, and a coil demolding process (step S6) in which the bent coil is removed from the bending jig.

[0028] Furthermore, a coil 100 manufactured by the coil manufacturing method of the present invention includes a planar coil portion 10 and a bent portion 20, as shown in FIG. 2. This coil 100 is formed into a hook shape by vertically extending a portion of a planar coil having a pair of long sides and a pair of short sides, in which a conductor wire is wound in multiple layers (or multiple rows and multiple layers). In the present invention, the conductor wire is an enameled wire, an enameled wire coated with an insulating film (a double-coated wire having two insulating layers), a composite wire in which multiple enameled wires are collectively coated with an insulating outer layer, or an enameled wire having a bonding layer made of a thermoplastic resin on its surface (hereinafter referred to as a self-bonding wire). The conductor wire is a round wire having a circular cross section or a rectangular wire having a square cross section.

[0029] The planar coil portion 10 has a pair of parallel portions 10a extending parallel to each other, and a connecting portion 10b connecting one ends of the pair of parallel portions together.

[0030] The bent portion 20 is formed by, for example, bending one longitudinal end (bent end) of the planar coil by 90 degrees. The upper end surface 21 of the bent portion 20 is formed so that the windings of each layer are on the same plane (see FIG. 6). Note that the bending angle is not limited to 90 degrees.

[0031] In the coil manufacturing method according to the first embodiment of the present invention, as shown in FIG. 1, first, in the planar coil forming step (step S1), a conductor wire (e.g., an enameled wire without a fusion layer on its surface or a self-bonding wire) is wound in multiple layers to form a planar coil having a pair of parallel portions 10a and a connecting portion 10b connecting one end of the pair of parallel portions. In this planar coil forming step, when an enameled wire without a fusion layer on its surface (or a double-coated wire with a double insulating layer) is used, adhesive varnish is applied to each layer of the pair of parallel portions 10a of the planar coil. In this case, since the adhesive varnish is applied, after winding, the planar coil is heated to the hardening temperature of the adhesive varnish (e.g., 230°C) for a predetermined time (e.g., 1 hour) to fix the winding. On the other hand, when a self-bonding wire is used, the winding is fixed by heating to the hardening temperature of the fusion layer. This heating serves both to anneal the wire itself and to relieve processing stress during winding. The planar coil is then cooled and removed from the winding jig T1.

[0032] In the planar coil forming process, when winding is performed to form each layer of the planar coil, a winding core (core) as shown in Fig. 3(A) is used, and a predetermined dimension ΔL is gradually reduced in the vertical direction (bending direction) at the end to be bent to form a step, and after bending a part of the planar coil in the vertical direction in the bending process, the upper end surface of the vertical part is made parallel to the surface of the planar coil (see Fig. 6). Also, as shown in Fig. 6, r1 is the inner radius of the bent part, r2 is the outer radius, and t is the thickness of the coil.

[0033] Here, when the bending angle is 90 degrees, the dimensional difference δ at the end on the bending side can be found from the ¼ circumferential distance using formula (1). δ=(2π×r2) / 4-(2π×r1) / 4 (1) Since r2 = r1 + t, (1) can be rewritten as (2). δ=1 / 2×π×t (2) This makes it possible to calculate the dimensional difference (predetermined dimension) ΔL between the layers. That is, ΔL=(1 / 2×π×t) / (d-1) (3) In the formula, π is the ratio of the circumference of a circle to its diameter (a constant), t is the thickness of the planar coil, and d is the number of winding layers. FIG. 3(B) shows a cross section of a planar coil formed in the planar coil forming step of the coil manufacturing method according to the present invention.

[0034] Next, in the first heating step (step S2), for example, the planar coil is placed in a coil bending jig T2 as shown in FIG. 4 or 5 and heated to a predetermined temperature. Here, in the case of a self-bonding wire, the planar coil obtained in the planar coil forming step is heated to the softening temperature (or melting temperature) of the fusion layer on the conductor surface. For example, if the fusion layer has a fusion temperature of 150°C, the heating temperature is set to 160-170°C. On the other hand, in the case of an enameled wire to which an adhesive varnish is applied in the planar coil forming step, the planar coil is heated to the softening temperature (or melting temperature) of the adhesive varnish (e.g., 180°C). Note that the softening temperature (or melting temperature) varies depending on the type of adhesive varnish, so the heating temperature can be set appropriately. Here, heating methods that can be used include a method using a constant temperature bath, a method in which the coil is heated by self-heating by applying electricity to the coil, and a method in which the jig is heated by high-frequency induction heating (IH) and the heat is transferred to the coil. Considering productivity, high-frequency induction heating is preferable, as it is expected to shorten the heating time. In experiments, it took 8 to 9 minutes to heat the coil to 170°C when the high-frequency induction heating output was 2 kW, and approximately 3 minutes when the output was 5 kW. In contrast, the method using a constant temperature bath required approximately 30 minutes or more. This first heating step softens the fusion layer, loosening the bond between the wires in each layer of the planar coil, minimizing stress caused by wire misalignment during bending in the next bending step. Furthermore, softening the fusion layer also reduces the friction between the wires during bending.

[0035] Next, in the bending process (step S3), a portion of the planar coil heated to a predetermined temperature is bent vertically. In this bending process, to prevent the coil winding from collapsing, side pressure jigs T2a of the coil bending jig T2 press down on both sides of the bent portion, and the bending process is performed while repeatedly loosening and tightening the pressure on both sides of the bent portion. In the present invention, the coil bending jig T2 is equipped with side pressure jigs T2a, which are configured to repeatedly loosen and tighten the pressure on both sides of the bent portion during bending. This reduces friction between the wires during bending. Figure 4 shows an example of the coil bending jig T2 used in the bending process. As shown in Figure 4, the coil bending jig T2 allows repeated manual loosening and tightening of the pressure. Figure 5 shows another example of the configuration of the coil bending jig T2 used in the bending process. As shown in Figure 5, the vibration mechanism T2b, which repeatedly loosens and tightens the clamp, can be a drive mechanism equipped with an air cylinder or servo motor. The vibration amplitude of the vibration mechanism T2b is determined so that the wire does not collapse. When bending the coil, care must be taken to ensure that the bending radius does not become excessively small. Since the elongation of the coating of the coil wire is generally guaranteed to be up to approximately 30%, it is desirable to ensure that the elongation due to the bending process does not exceed 30%. However, in reality, the elongation during bending is not limited to the 90-degree range, but is distributed to the straight sections by approximately 3 to 10%, so this amount must also be taken into consideration.

[0036] Next, in the second heating step (step S4), the bent coil formed in the forming step is heated at a predetermined temperature (e.g., 230°C to 240°C) for a predetermined time (e.g., 1.5 hours) to anneal the winding. Here, for example, the bent coil is attached to a forming jig T3, and the bent coil and the forming jig T3 are heated together. By heating the processed copper, the fine crystals are recrystallized and softened, reducing stress during the coil bending and forming process and minimizing springback. This allows the coil dimensions to be finished with high precision after bending. Here, heating methods that can be used include a method using a constant temperature bath, a method of applying electricity to the coil to heat it up by itself, and a method of heating the jig by high-frequency induction heating (IH) and conducting heat to the coil. However, the heating in the planar coil forming step (step S1) and the first heating step (step S2) may also serve these purposes.

[0037] Next, in a cooling step (step S5), the bent coil and the forming jig T3 are cooled together to room temperature. Finally, in a coil demolding step (step S6), the bent coil is removed from the forming jig T3, and the coil 100 is obtained.

[0038] As described above, the coil manufacturing method of the first embodiment of the present invention involves winding a conductor wire in multiple layers (or multiple rows and multiple layers), heating the formed planar coil to a predetermined temperature, bending a portion of the planar coil at a predetermined angle in a direction perpendicular to the plane of the planar coil in a bending process, and then annealing the formed bent coil by heating it at a predetermined temperature for a predetermined time. In the planar coil forming process, when forming each layer of the coil, the end to be bent is gradually reduced in size in the vertical direction to form a step, thereby maintaining the characteristics of the coil 100 without reducing the alignment of the wire due to the bending process. In addition, by performing the bending process using a coil bending jig T2 equipped with a pressure jig T2a, and then heating and annealing the bent coil after the bending process, the bent portion of the coil 100 does not protrude in the lateral direction as shown in FIG. 12, and stress between and within the coil wire is suppressed, thereby suppressing springback that occurs in the formed coil product, and the coil dimensions after the bending process can be finished with high precision.

[0039] FIG. 7 shows the steps of manufacturing a hooked coil 100A using a coil manufacturing method according to a second embodiment of the present invention. FIG. 8 shows an example of a forming jig used in the forming step. FIG. 9 shows the state in the forming step in which the bent coil obtained in the bending step is placed on the forming jig and pressed down to form it. FIG. 10 shows the state in which a jig is attached to press down the side of the coil in the forming step. FIG. 11 shows the state in which a jig is attached to press down the hooked bent end of the coil in the forming step. In this embodiment, the L-shaped bend angle is 90 degrees, and the flat coil portion 10A is curved.

[0040] As shown in FIG. 7, the coil manufacturing method according to this embodiment includes a planar coil forming process (step S11) in which a conductor wire is wound in multiple layers (or multiple rows and multiple layers) to form an air-core planar coil, a first heating process (step S12) in which the planar coil formed in the planar coil forming process is heated to a predetermined temperature, a bending process (step S13) in which at least a portion of the planar coil heated in the first heating process is bent at a predetermined angle in a direction perpendicular to the surface of the planar coil, a second heating process (step S14) in which the bent coil formed in the bending process is heated to a predetermined temperature, a forming process (step S15) in which the bent coil heated in the second heating process is formed into a predetermined shape and dimensions using a forming jig, a third heating process (step S16) in which the bent coil formed in the forming process is heated at a predetermined temperature for a predetermined time, a cooling process (step S17) in which the bent coil is cooled, and a coil demolding process (step S18) in which the bent coil is removed from the bending jig.

[0041] Furthermore, the coil 100A manufactured by the coil manufacturing method according to this embodiment includes a planar coil portion 10A and a bent portion 20A, and the planar coil portion 10A has a curved shape, as shown in Fig. 12. In this embodiment, the conductor wire is an enameled wire coated with an insulating film (including a double-coated wire having a double insulating layer) or a self-bonding wire.

[0042] As shown in FIG. 7 , the coil manufacturing method according to this embodiment begins with a planar coil formation step (step S11) in which a conductor wire (e.g., an enameled wire without a fusion layer on its surface or a self-bonding wire) is wound in multiple layers (or multiple rows and multiple layers) to form a planar coil having a pair of parallel portions 10a and a connecting portion 10b connecting one end of the pair of parallel portions. In this planar coil formation step, if an enameled wire without a fusion layer on its surface (or a double-coated wire with a double insulating layer) is used, adhesive varnish is applied to each layer of the pair of parallel portions 10a of the planar coil. In this case, since the adhesive varnish is applied, the planar coil is heated for a predetermined time up to the curing temperature of the adhesive varnish after winding to fix the winding. On the other hand, if a self-bonding wire is used, the winding is fixed by heating up to the curing temperature of the adhesive layer. Furthermore, in this planar coil forming process, when winding wire and forming each layer of the planar coil, the predetermined dimension ΔL is gradually reduced in the vertical direction (bending direction) at the end to be bent to form a step, and after bending a part of the planar coil in the vertical direction in the bending process, the upper end surface of the vertical part is made parallel to the surface of the planar coil (see Figure 6).

[0043] Next, in the first heating step (step S12), for example, the planar coil formed in the planar coil forming step is set in a bending jig T2 as shown in Figures 4 and 5 and heated to a predetermined temperature. Here, in the case of a self-bonding wire, the planar coil obtained in the planar coil forming step is heated to the softening temperature (or melting temperature) of the fusion layer on the conductor surface. For example, if the fusion layer has a fusion temperature of 150°C, the heating temperature is 160 to 170°C. On the other hand, in the case of an enameled wire to which an adhesive varnish is applied in the planar coil forming step, the planar coil is heated to the softening temperature of the adhesive varnish (e.g., 180°C). Note that the softening temperature varies depending on the type of adhesive varnish, so the heating temperature can be set appropriately. Here, as a heating method, it is preferable to use a method in which the jig is heated by high-frequency induction heating (IH) and heat is conducted to the coil.

[0044] Next, in the bending process (step S13), a portion of the planar coil heated to a predetermined temperature is bent vertically using a bending jig T2 as shown in FIGS. 4 and 5. In this bending process, to prevent the coil windings from collapsing, both sides of the bent portion are pressed down with the presser jigs T2a of the coil bending jig T2, and the bending process is performed by repeatedly loosening and tightening the pressure on both sides of the bent portion. In the present invention, the coil bending jig T2 is configured to repeatedly loosen and tighten the pressure on both sides of the bent portion during bending. This reduces friction between the wire during bending. In the case of the coil bending jig T2 shown in FIG. 4, the mechanism that repeatedly loosens and tightens the presser is performed manually. Alternatively, as shown in FIG. 5, a driving mechanism having an air cylinder or servo motor can be used for the vibration mechanism T2b that repeatedly loosens and tightens the presser. The vibration amplitude of the vibration mechanism T2b is determined within a range that prevents the wire from collapsing. When bending the coil, care must be taken to ensure that the bending radius is not too small.

[0045] Next, in the second heating step (step S14), the bent coil formed in the bending step and bent into a hook shape is heated to a predetermined temperature. Here, in the case of a self-bonding wire, the planar coil obtained in the planar coil forming step is heated to the softening temperature of the bonding layer on the surface of the conductor. For example, if the bonding layer has a bonding temperature of 150°C, the heating temperature is 160 to 170°C. On the other hand, in the case of an enameled wire to which an adhesive varnish has been applied in the planar coil forming step, the planar coil is heated to the softening temperature of the adhesive varnish (for example, 180°C). Here, as a heating method, it is preferable to use a method in which a jig is heated by high-frequency induction heating (IH) and heat is conducted to the coil.

[0046] Next, in the forming process (step S15), the heated L-shaped bent coil is subjected to a forming process to determine its shape and outer dimensions using a forming jig T3 (see FIG. 8). For example, as shown in FIG. 9, the bent coil is first set in a forming jig body T3a, and a back pressure member T3b is attached and pressed to form the flat coil portion 10A of the bent coil into a predetermined shape (e.g., a curved shape bent toward the rear). The forming process is not limited to a curved shape bent toward the rear. The forming jig T3 can be designed as needed. Next, a side pressure member T3c that presses the side surfaces of the flat coil portion 10A of the bent coil is attached by pressing in the direction of the arrow in FIG. 10, thereby adjusting the shape and dimensions of the side surfaces. Next, a top pressure member T3d and end side pressure members T3e, T3f, and T3g that press the top and four side surfaces of the bent portion 20A of the bent coil are attached by pressing in the direction of the arrow in FIG. 11, thereby adjusting the shape and dimensions of the bent portion 20A.

[0047] After this molding step, if there is further molding processing to be performed on other parts, the above-mentioned steps S14 and S15 are repeated (broken arrow in FIG. 7).

[0048] Next, in the third heating step (step S16), the bent coil is heated at a predetermined temperature (e.g., 230°C to 240°C) for a predetermined time (e.g., 1.5 hours) to maintain the final shape of the bent coil formed in the forming step. This annealing treatment is performed, and the adhesive layer or adhesive varnish is cured. Here, for example, the bent coil is attached to a forming jig T3, and the bent coil and forming jig T3 are heated together. By heating the processed copper, the fine crystals are recrystallized and softened, reducing stress during the coil bending and forming processes and minimizing springback. This allows the coil dimensions to be finished with high precision after bending. Here, the preferred heating method is to heat the jig using high-frequency induction heating (IH) and conduct heat to the coil.

[0049] Next, in a cooling step (step S17), the bent coil and the forming jig T3 are cooled together to room temperature. Finally, in a coil demolding step (step S18), the bent coil is removed from the forming jig T3, and the coil 100A is obtained.

[0050] As described above, the coil manufacturing method of the second embodiment of the present invention involves winding a conductor wire in multiple layers (or multiple rows and multiple layers), heating the resulting planar coil to a predetermined temperature, bending a portion of the planar coil at a predetermined angle in a direction perpendicular to the plane of the planar coil in a bending process, heating the resulting bent coil at a predetermined temperature for a predetermined time, and then shaping the shape and outer dimensions using a forming jig T3 in a forming process. The bent coil is then heated at a predetermined temperature for a predetermined time for an annealing treatment, thereby maintaining the characteristics of the coil 100A without reducing the degree of alignment of the wire due to the bending process. Furthermore, by performing the bending process using a coil bending jig T2 equipped with a pressure jig T2a, and then heating and annealing the bent coil after the bending process, the bent portion of the coil 100A does not protrude laterally, as shown in FIG. 12, and stress between and within the coil wires is suppressed, thereby suppressing springback in the formed coil product, thereby enabling the coil dimensions to be finished with high precision after bending.

[0051] In the above-described embodiment, the first heating step and the bending step are each performed once, but the present invention is not limited to this. For example, the first heating step and the bending step may be performed multiple times in multiple different temperature zones.

[0052] In the above-described embodiment, the coil bending step involves bending at least a portion of the planar coil vertically (90 degrees), but the present invention is not limited to this. The coil may be bent at an angle of less than 90 degrees or at an angle of more than 90 degrees.

[0053] The present invention is not limited to the above-described embodiments, and its technical scope includes various modified design forms within the scope that do not deviate from the gist of the invention described in the claims. [Industrial Applicability]

[0054] The present invention can be used to form a part of a planar coil in which a conductor is wound in multiple layers (or multiple rows and multiple layers) into a hook shape or the like by bending the part at a predetermined angle in a direction perpendicular to the surface of the planar coil. [Explanation of symbols]

[0055] 1A planar coil 1B Hooked coil 1a, 10, 10A Planar coil section 10a Parallel section 10b Connection part 1b, 20, 20A Bending part 21 End face 100, 100A coil T1 Winding jig T2 Coil bending jig T2a Side holding jig T2b vibration mechanism T3 molding jig T3a molding jig body T3b Back side support member T3c Side support member T3d Upper surface holding member T3e, T3f, T3g End side holding member

Claims

1. a planar coil forming step of winding a conductor wire in multiple layers (or multiple rows and multiple layers) to form an air-core planar coil; a first heating step of heating the planar coil formed in the planar coil forming step to a predetermined temperature; a bending step of bending at least a portion of the planar coil heated in the first heating step at a predetermined angle in a direction perpendicular to a surface of the planar coil; a second heating step of heating the bent coil formed in the bending step at a predetermined temperature for a predetermined time, A coil manufacturing method characterized in that in the bending process, both sides of the bent portion are pressed with a pressing jig, and the bending process is performed by repeatedly loosening and tightening the pressure on both sides of the bent portion.

2. a forming step of forming the bent coil formed in the bending step into a predetermined shape and dimensions using a forming jig; 2. The method for manufacturing a coil according to claim 1, further comprising a third heating step of heating the bent coil formed in the forming step at a predetermined temperature for a predetermined time.

3. the planar coil has a pair of parallel portions extending parallel to each other and a pair of connecting portions connecting ends of the pair of parallel portions, 3. The method for manufacturing a coil according to claim 1, wherein in the planar coil forming step, adhesive varnish is applied to only the pair of parallel portions of the planar coil for each layer while the planar coil is wound.

4. the conductive wire has a fusion layer on its surface; 3. The method for manufacturing a coil according to claim 1, wherein the first heating step heats the planar coil to a softening temperature of the fusion layer.

5. 5. The method for manufacturing a coil according to claim 1, wherein the first heating step and the bending step are performed in a plurality of different temperature zones.

6. 6. The method for manufacturing a coil according to claim 1, wherein in the planar coil forming step, when forming each layer of the planar coil, the end to be bent is gradually reduced in size toward the vertical direction to form a step.

7. 3. The coil manufacturing method according to claim 2, wherein the first heating step, the second heating step, and the third heating step use a heating method in which a jig in which the planar coil or the bent coil is set is heated by high-frequency induction heating, and heat is conducted from the jig to the planar coil or the bent coil.

8. A coil bending jig for manufacturing a hook-shaped coil in which a part of a planar coil in which a conductor wire is wound in multiple layers is bent at a predetermined angle in a direction perpendicular to the surface of the planar coil, a pressing jig for pressing both side surfaces of the bent portion of the coil; The coil bending jig is characterized in that the pressing jig is configured to repeatedly loosen and tighten the pressure on both sides of the bent portion when performing bending processing.

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