JP7595052B2 - Manufacturing method for non-contact power supply coil - Google Patents

Description

One embodiment of the present invention relates to a method for manufacturing a coil for contactless power supply.

In recent years, there has been research being conducted into the application of contactless power transmission technology to power electric vehicles (EVs) and plug-in hybrid vehicles (PHVs), rather than contactless power transmission using cables. Contactless power supply technology supplies power to electric vehicles by wirelessly transmitting electricity between a power transmission (primary side) planar coil embedded in the road surface of a power supply station and a power receiving (secondary side) planar coil installed at the bottom of the electric vehicle, facing each other with a gap of several tens of centimeters between them.

For example, coils used in contactless power supply and the like use Litz wire to reduce loss. A cable that supplies high frequency is connected to the coil unit that houses the coil. Litz wire is used as the conductor of this cable to reduce loss. Connectors such as round terminals are required for connection to the coil lead wire terminals and cable terminals. However, terminal processing of Litz wire requires the removal of wire insulation and loss occurs due to connector connection, so a structure that serves both the coil lead wire and the cable is adopted.

JP 2019-23983 A Special table 2013-524419 publication JP 2019-118183 A JP 2010-282914 A

A common insulation is necessary for cables from the viewpoint of strengthening insulation. In addition, it is undesirable for the coil wire to be provided with a common insulation due to constraints such as the external dimensions and winding process. Therefore, the cable portion must be covered with a heat shrink tube or the like after coil processing to strengthen the insulation. If the cable is longer than several tens of meters, the process of covering the conductor with a heat shrink tube to strengthen the insulation must be repeated. Repeating this process increases the effort and time required for manufacturing the non-contact power supply coil 10.

One of the objectives of one embodiment of the present invention is to provide a manufacturing method that reduces the labor required to manufacture coils for contactless power supply.

In one embodiment of the present invention, a method for manufacturing a coil for contactless power supply involves forming a cut in the common insulation in the circumferential direction of the current-carrying wire at a location a first predetermined length from one end of the current-carrying wire with common insulation, stripping the common insulation from the cut to the other end over a second predetermined length, and placing the current-carrying wire from which the common insulation has been stripped in an area where the coil is to be placed, by sequentially repeating the following steps to form a coil from the current-carrying wire from which the common insulation has been stripped.

In the above configuration, the first predetermined length may be longer than the second predetermined length.

In the above configuration, the material of the common insulation may be heat-resistant polyolefin, polyethylene, polyvinyl chloride, fluorine-based resin, polyurethane resin, polyester resin, polyimide resin, or polyamide resin.

In the above configuration, after forming the coil, a process of crimping a terminal to one end of the common insulated conductive wire may be included.

In the above configuration, a filamentous fiber or fiber layer may be provided between the current-carrying wire and the common insulation.

In the above configuration, the current-carrying wire may be a Litz wire made by twisting together a number of conductor wires with an insulating coating on the outer periphery.

One embodiment of the present invention can provide a manufacturing method that reduces the labor required to manufacture coils for contactless power supply.

FIG. 2 is a plan view showing the structure of a coil for contactless power supply. (A) is a side view of a litz wire, and (B) is a cross-sectional end view of the litz wire at line segment A-A' in (A). FIG. 4 is a flow diagram illustrating a method for manufacturing a coil for contactless power supply according to an embodiment of the present invention. 1A is a diagram illustrating step S201 of a method for manufacturing a contactless power supply coil according to an embodiment of the present invention, and FIG. 1B is a diagram illustrating step S202 of a method for manufacturing a contactless power supply coil according to an embodiment of the present invention. 11 is a diagram illustrating step S203 of the method for manufacturing a coil for contactless power supply according to the embodiment of the present invention. FIG. FIG. 11 is a diagram illustrating step S204 of the method for manufacturing a coil for contactless power supply according to one embodiment of the present invention. (A) is a side view of the litz wire, and (B) is a cross-sectional end view of the litz wire at line segment B-B' in (A).

One embodiment of the present invention will be described below with reference to the drawings. The embodiment described below is an example of an embodiment of the present invention, and the present invention is not limited to these embodiments.

In the drawings referred to in this embodiment, identical parts or parts having similar functions are given the same or similar reference symbols (reference symbols consisting of a number followed by A, B, etc.). In addition, the dimensional ratios of the drawings may differ from the actual ratios for the convenience of explanation, and some components may be omitted from the drawings. Note that ordinal numbers such as "first," "second," and "third" in this specification are used only to simplify the explanation and should not be interpreted in a limiting manner.

First Embodiment
A contactless power supply device is configured by arranging a primary-side contactless power transmitting device and a secondary-side contactless power receiving device opposite each other. The primary-side contactless power transmitting device, which supplies power, and the secondary-side contactless power receiving device, which receives power, are configured with substantially the same elements in the coil portion, and although one side will be described here, it goes without saying that the other side is similar.

<Structure of the non-contact power supply coil>
Fig. 1 is a plan view showing the structure of a contactless power supply coil 10. As shown in Fig. 1, the contactless power supply coil 10 has a coil 12, cables 14, 16 provided at both ends of the coil 12, and terminals 22, 24 connected to the ends of the cables 14, 16. The coil 12 is arranged in a spiral shape.

The current-carrying wire used in the coil 12 may be a conductor (a linear conductor made of copper or aluminum) or a litz wire. In addition, a wire in which a conductor (a linear conductor made of copper or aluminum) is coated with an insulating layer may be used as the current-carrying wire. Furthermore, a self-bonding wire in which a self-bonding layer is provided on the outermost layer of a conductor coated with an insulating layer may be used as the current-carrying wire. The cables 14 and 16 may be those in which a common insulation is directly applied to the current-carrying wire. In addition, the cables 14 and 16 may be those in which a common insulation is applied from above the thread-like fiber while maintaining the shape by winding a thread-like fiber around the litz wire 101. In this embodiment, a case in which a litz wire directly coated with a common insulation is used as the current-carrying wire will be described. Hereinafter, the configuration of a litz wire directly coated with a common insulation will be described with reference to FIG. 2.

Figure 2 is a schematic diagram of the litz wire 101. Figure 2 (A) is a side view of the litz wire 101. Figure 2 (A) shows the boundary between the area of the litz wire 101 that functions as the cable 14 and the area that functions as the coil 12. The area of the litz wire 101 that functions as the cable 14 is provided with common insulation 103. In the following description, the litz wire provided with the common insulation 103 is referred to as the litz wire 101A. The area of the litz wire 101 that does not have the common insulation 103 functions as the coil 12.

Figure 2(B) is a cross-sectional end view of Litz wire 101A taken along line segment A-A' in Figure 2(A).

As shown in FIG. 2B, the litz wire 101A has a configuration in which the litz wire 101 is provided with a common insulation 103. The litz wire 101 has a plurality of strands 107 with an insulating coating 107b on the outer circumferential surface of the conductor 107a. The strands 107 may be so-called enameled wires. The conductor 107a of the enameled wire is preferably copper or a copper alloy, and may be made of aluminum, an aluminum alloy, or a clad material of copper and aluminum. The insulating coating 107b of the enameled wire may be made of polyurethane, polyvinyl formal, polyurethane nylon, polyester, polyester nylon, polyester imide, polyamide imide, polyester imide/polyamide imide, polyimide, or the like. The insulating coating 107b is preferably a resin material that melts with high-temperature solder when both ends of the litz wire 101 are soldered to the terminals 22 and 24.

The litz wire 101 is composed of bundles 109 composed of multiple wires 107. In one embodiment, the litz wire 101 may have a twisted wire structure in which multiple bundles 109 are twisted. Furthermore, the multiple bundles 109 of the litz wire 101 are covered with a common insulation 103. For example, heat-resistant polyolefin, polyethylene (PE), polyvinyl chloride (PVC), fluorine-based resin (PTFE), polyurethane resin, polyester resin, polyimide resin, polyamide resin, etc. are used as the common insulation 103. The extrusion temperature during extrusion coating to cover the common insulation 103 is, for example, about 120°C to 300°C. When the common insulation 103 is applied to the multiple bundles 109 of the litz wire 101, the multiple bundles 109 are covered with the common insulation 103. The wire diameter of the litz wire 101A and the litz wire 101 is, for example, about 4 mm to 5 mm.

In this embodiment, the cables 14, 16 and the coil 12 are manufactured using the litz wire 101A to which the common insulation 103 has already been applied. In other words, the cables 14, 16 use the litz wire 101A to which the common insulation 103 has already been applied, and the coil 12 uses the litz wire 101 from which the common insulation 103 has been stripped.

The coil 12 is manufactured by arranging the litz wire 101 on the support substrate 30 in a plane and winding it from the inner circumference side to the outer circumference side to form a spiral shape. The winding of the litz wire 101 may be manufactured in a spiral shape by winding it from the outer circumference side to the inner circumference side. Arranging it on a plane means arranging it on a plane that intersects (is perpendicular to) the axis around which the coil is wound. The position of the innermost circumference of the coil 12 is position A0, and the position of the outermost circumference of the coil 12 after winding n times in the winding direction B is position An. In other words, the length of the litz wire 101 from position A0 to position An corresponds to the coil 12. The outer shape of the coil 12 is approximately rectangular (with rounded corners). In FIG. 1, the outer shape of the coil 12 is square, but it may be rectangular. In either case of a square or a rectangle, it is sufficient that the corners are rounded. Coil 12 is installed, for example, on the primary side (power transmission side or power supply side), for example, on the road surface of an EV charging station.

Since the coil 12 is composed of multiple bundles 109 of the Litz wire 101, if the coil 12 is simply wound in a spiral shape on a flat surface, the multiple bundles 109 will come apart during transportation. Therefore, the multiple bundles 109 may be fixed in place by wrapping adhesive tape or the like around multiple points in accordance with the winding width of the coil 12 to prevent the shape from collapsing.

The support substrate 30 is formed of a synthetic resin material. It is desirable that the material of the support substrate 30 has little effect on the electric field and magnetic field formed by wireless power supply from one coil 12 to the other coil, and has little change in shape due to temperature change. Preferably, the material of the support substrate 30 has little thermal expansion between, for example, -30°C and 120°C. For example, polycarbonate resin is used as the material of the support substrate 30. Also, polypropylene resin may be used as the material of the support substrate 30. Also, in order to fix the position of the coil 12, a groove for maintaining the shape of the coil 12 may be provided in the support substrate 30. For example, as the form of the coil 12, it is preferable to wind the coil 12 with a gap between the windings. In order to provide a gap between the windings, a support substrate 30 with a groove with a gap formed therein may be used. A support substrate 30 with a groove with a gap formed therein is also called a bobbin.

The outer and inner diameters of the coil 12 are set appropriately according to the application of the contactless power supply device. The conditions for a contactless power supply coil for EVs are an outer coil diameter of 250 mm to 600 mm and an inner coil diameter of approximately 100 mm to 200 mm. In addition, since the transmission frequency is set to 85 kHz, the coil 12 must have an inductance that resonates with this frequency. When using Litz wire as the coil 12, the number of turns n of the coil 12 may be approximately 8 to 22 turns.

Cable 14 and cable 16 each have a predetermined length. There is no particular limit to the predetermined length that allows cables 14 and 16 to function, but it may be, for example, several meters to several tens of meters. The length of cable 14 and the length of cable 16 may be the same or different.

The terminals 22, 24 are electrically connected to the ends of the cables 14, 16. The terminals 22, 24 are composed of crimping parts 22a, 24a and fixing parts 22b, 24b with fixing holes. The crimping parts 22a, 24a are composed of a cylindrical metal member. The end of the cable 14 is crimped by being inserted into the cylindrical metal member of the crimping part 22a. This electrically connects the cable 14 to the terminal 22. Similarly, the cable 16 is electrically connected to the terminal 24. At the ends of the cables 14, 16, the common insulation 103 at the end of the Litz wire 101A may be partially stripped off.

<Method of manufacturing a coil for contactless power supply>
A method for manufacturing the contactless power supply coil 10 according to one embodiment of the present invention will be described with reference to FIGS.

Figure 3 is a flow diagram illustrating the steps of a method for manufacturing a coil 10 for contactless power supply according to one embodiment of the present invention. It is not desirable for the coil wire to be provided with common insulation due to restrictions on the external dimensions and winding process. Therefore, in the area to function as the coil 12, an operation is required to strip off the common insulation 103 provided on the current-carrying wire. In this embodiment, a case where the coil 12 is formed using a litz wire 101A that has been previously provided with the common insulation 103 will be described. Although a detailed description will be omitted, the coil 12 can be formed in the same manner as the litz wire 101A when the coil 12 is formed using a conductor, electric wire, or self-bonding wire that has been previously provided with common insulation.

First, a cut 112 is formed in the common insulation 103 in the circumferential direction of the litz wire 101A at a predetermined length L1 from one end of the litz wire 101A to which the common insulation 103 is applied (see step S201 shown in FIG. 3). FIG. 4(A) is a diagram explaining step S201. As shown in FIG. 4(A), the cut 112 is formed at a predetermined length L1 from one end of the litz wire 101A. Here, the predetermined length L1 from one end of the litz wire 101A corresponds to the length that functions as a cable. The cut 112 is not formed in the litz wire 101, but is formed only in the common insulation 103.

Next, the common insulation 103 is stripped from the cut portion 112 toward the other end over a predetermined length L2 (see step S202 shown in FIG. 3). FIG. 4(B) is a diagram for explaining step S202. As shown in FIG. 4(B), the common insulation 103 is stripped from the cut portion 112 toward the other end over a predetermined length L2. This exposes the litz wire 101 from the common insulation 103. The operation of stripping the common insulation 103 may be performed using a known conductor insulation coating stripping device. Here, the predetermined length L2 from the cut portion 112 toward the other end is not particularly limited, but it is preferable that the predetermined length L2 is shorter than the equivalent length L1 of the cable 14. This makes it easier to arrange the litz wire 101 in a predetermined position.

Next, the litz wire 101 from which the common insulation 103 has been stripped is placed in the area 32 in which the coil 12 is to be placed (see step S203 shown in FIG. 3). FIG. 5 is a diagram for explaining step S203. The coil 12 is placed, for example, on the support substrate 30. The support substrate 30 is provided with an area 32 in which the coil 12 is to be placed. An area corresponding to a predetermined length L2 of the litz wire 101 is placed in the area 32 as the coil 12. The litz wire 101 is placed from the inner circumference side toward the outer circumference side. In FIG. 5, winding begins from the innermost position A0 in the winding direction B. The number of times the litz wire 101 is wound in one operation is determined according to the predetermined length L2 of the litz wire 101 and the inner diameter of the coil 12. Therefore, the number of times the litz wire 101 is wound in one operation is not limited. FIG. 5 shows the state in which the litz wire 101 is wound twice as the coil 12 in one operation. The winding end position of the litz wire 101 is position A1. At this time, adjacent litz wires 101 are arranged with a certain distance between them.

After that, if the winding of the litz wire 101 is not completed (see step S204; No in FIG. 3), the operation of stripping off the common insulation 103 from the cut portion 112 toward the other end over a predetermined length L2 (step S202) and the operation of placing the litz wire 101 from which the common insulation 103 has been stripped in the area 32 where the coil is to be placed (step S203) are repeated. FIG. 6 shows the state after the operation shown in step S202 and the operation shown in step S203 are repeated multiple times. The position where the winding of the litz wire 101 ends is position A2. The operation of stripping off the common insulation 103 of the litz wire 101 is performed multiple times, and the predetermined length for stripping off the common insulation 103 may be different for each operation.

When the winding of the litz wire 101 is finished (see step S204; Yes in FIG. 3), the coil 12 is completed (step S205). In this embodiment, the coil 12 is completed by winding the litz wire 101 eight times. As shown in FIG. 1, a predetermined length from the end position An of the winding of the coil 12 is made to function as the cable 16. Therefore, the litz wire 101A is cut at a predetermined length from the position An of the coil 12.

Next, terminal 22 is crimped to the end of cable 14, and terminal 24 is crimped to the end of cable 16 (step S206). Furthermore, by crimping the end of cable 14 and terminal 22, cable 14 and terminal 22 are integrated. By crimping the end of cable 16 and terminal 24, cable 16 and terminal 24 are integrated. As a result, the end of cable 14 and terminal 22 are electrically connected, and the end of cable 16 and terminal 24 are electrically connected. Through the above steps, the coil 10 for contactless power supply can be manufactured.

In this embodiment, an example is described in which the terminal 22 is crimped to the end of the cable 14 after the coil 12 is formed, but the terminal 24 may be crimped to the end of the cable 14 before the coil 12 is formed.

Conventionally, when forming a coil using a current-carrying wire that does not have common insulation, after forming the coil, it is necessary to cover the part that corresponds to the cable with a heat shrink tube to strengthen the insulation. If the cable is longer than several tens of meters, it is necessary to repeat the process of covering the current-carrying wire with a heat shrink tube to strengthen the insulation. Repeating this process increases the effort and time required to manufacture the coil 10 for contactless power supply.

In contrast, in the manufacturing method of the coil 10 for contactless power supply according to one embodiment of the present invention, the coil 12 is manufactured using a current-carrying wire that has been previously treated with the common insulation 103. At this time, a predetermined length from one end of the current-carrying wire that has been treated with the common insulation 103 is made to function as the cable 14 or cable 16. This saves the effort and time of repeatedly covering the current-carrying wire with a heat shrink tube to strengthen the insulation and form the common insulation 103 in order to make the cables 14, 16 function as cables 14, 16 when the cables 14, 16 are several meters to several tens of meters long. In other words, it is possible to reduce labor in the manufacturing of the coil 10 for contactless power supply.

Furthermore, when winding the coil after stripping off the common insulation 103 to the required length in a single operation, if the required length of the coil is long (the number of turns is large), errors may occur during winding of the coil, and the end position of the coil winding (e.g., position An in Figure 1) may shift. For example, when a Litz wire is used as the coil, if the required length of common insulation 103 is stripped off in a single operation, the Litz wire itself will become flattened, making it difficult to wind. Also, the twist of the Litz wire will come undone, making winding even more difficult.

As in the manufacturing method of the contactless power supply coil 10 according to one embodiment of the present invention, by repeatedly performing the operation of stripping off the common insulation 103 from the litz wire 101 and the operation of placing the litz wire 101 in the area where the coil is to be placed, it is possible to prevent the litz wire 101 itself from becoming flattened or the twist of the litz wire 101 from coming undone. In other words, the litz wire 101 from which the common insulation 103 has been stripped can be wound while maintaining the shape of the litz wire 101 due to the common insulation 103. This makes it possible to reduce the labor required to manufacture the contactless power supply coil.

In addition, when the litz wire 101 is directly coated with the common insulation 103, the common insulation 103 replaces the thread-like fiber. Therefore, the litz wire 101 can be prevented from coming apart during the winding of the coil. In addition, since there is no need to wind a thread around the litz wire 101, the manufacturing cost can be reduced. When the common insulation 103 is applied to the litz wire wound with a thread, the thread may melt due to the extrusion temperature when covering the common insulation 103. If the melted thread and the common insulation 103 are bonded together, it may be difficult to peel the common insulation 103 from the litz wire 101 when peeling the common insulation 103 off. In this embodiment, since the common insulation 103 is directly coated on the litz wire 101, the above-mentioned materials can be appropriately selected and used as the material for the common insulation 103. In addition, when a conductor, an electric wire, or a self-bonding wire is used as the current-carrying wire, the above-mentioned materials can be appropriately selected and used as the material for the common insulation 103.

In this embodiment, the coil 12 is configured using one current-carrying wire, but the present invention is not limited to this. The coil 12 may be configured using two current-carrying wires, that is, double-wound.

In the case of coil 12 using litz wire as the current-carrying wire, for example, a first litz wire that has been previously treated with common insulation is placed in the area where the coil is to be placed according to steps S201 to S205 of the flow diagram shown in FIG. 3. This operation is performed until the litz wire is wound n times to form coil 12. Next, a second litz wire that has been previously treated with common insulation is placed in the area where the coil is to be placed according to steps S201 to S205 of the flow diagram shown in FIG. 3. This operation is performed until the litz wire is wound n times to form coil 12. Finally, the two litz wires that have been previously treated with common insulation may be joined together to form a cable, and a terminal may be crimped to the end of the cable.

Alternatively, for the first Litz wire that has been previously subjected to common insulation, the Litz wire is placed in the area where the coil is to be placed according to steps S201 to S203 of the flow diagram shown in FIG. 3. Next, for the second Litz wire that has been previously subjected to common insulation, the Litz wire 101 is placed in the area where the coil is to be placed according to steps S201 to S203 of the flow diagram shown in FIG. 3. In this way, the operation of stripping off the common insulation of the Litz wire and the operation of placing the Litz wire in the area where the coil is to be placed may be repeated alternately for the first Litz wire that has been previously subjected to common insulation and the second Litz wire that has been previously subjected to common insulation. After the Litz wire of the first Litz wire and the Litz wire of the second Litz wire are each wound n times to form the coil 12, the two Litz wires may finally be joined together to form a cable, and a terminal may be crimped at the end of the cable.

Second Embodiment
In the first embodiment, an example was described in which the common insulation 103 was applied in contact with the litz wire 101. In the present embodiment, a method for forming a coil using the litz wire 101 to which thread-like fibers are applied and then the common insulation is applied will be described with reference to FIG.

Figure 7 is a schematic diagram of the litz wire 101. Figure 7 (A) is a side view of the litz wire 101. Figure 7 (A) shows the boundary between the area of the litz wire 101 that functions as the cable 14 and the area that functions as the coil 12. In the area of the litz wire 101 that functions as the cable 14, the filamentous fiber 108 is wound around the litz wire 101, and the common insulation 103 is applied from above the filamentous fiber 108. In the following description, the litz wire that is applied with the filamentous fiber 108 and the common insulation 103 is referred to as the litz wire 101B. In addition, the area of the litz wire 101 that is not applied with the common insulation 103 functions as the coil 12A.

Figure 7 (B) is a cross-sectional end view of Litz wire 101B taken along line segment B-B' in Figure 7 (A).

In FIG. 7(B), the litz wire 101B has a configuration in which the litz wire 101 is provided with thread-like fibers 108 and common insulation 103. The configuration of the litz wire 101 is similar to the configuration of the litz wire 101 shown in FIG. 2(B). In FIG. 2(B), the thread-like fibers 108 are provided on a bundle 109 made up of multiple strands 107.

As explained in the first embodiment, when the filamentous fiber 108 is wound around the Litz wire 101 and then the common insulation 103 is applied, the filamentous fiber 108 may melt due to the temperature when covering the common insulation 103. However, by selecting the material of the common insulation 103 and the material of the filamentous fiber 108, it is possible to cover the common insulation 103 without melting the filamentous fiber 108. Alternatively, even if the filamentous fiber 108 melts when covering the common insulation 103, it is possible to prevent the filamentous fiber 108 and the common insulation 103 from adhering to each other.

As the material of the thread-like fiber 108, at least one of polyester synthetic fiber Tetron thread, fiber acetate thread such as acetyl cellulose, and heat-sealed nylon fiber is used. Tetron thread is an insulating fiber thread made of polyester synthetic resin with a melting point of, for example, 250°C to 255°C, and is resistant to pulling and abrasion, has very little stretching, is particularly hygroscopic, and has good insulation properties. Acetate thread is a fiber thread for melt adhesion that is mainly made of acetyl cellulose, and melts and fuses with the surroundings when a solvent such as acetone is sprayed on it, and solidifies as the solvent evaporates. Therefore, when the acetate thread melts, the effect of improving the shape retention of the coil as a whole is also obtained. In addition, the melting point of the heat-sealed nylon fiber is lower than that of the Tetron thread, for example, about 120°C. Therefore, if, for example, a combination of heat-sealed nylon fiber and Tetron yarn is used as the thread-like fiber 108, the heat-sealed nylon fiber melts before the Tetron yarn when heat is applied, providing the same effect as a solvent.

The thread-like fiber 108 may be a combination of two or more threads, including a combination of multiple threads twisted together, or a combination of multiple threads arranged in a ribbon shape. The ratio of the combined threads may be, for example, 3:1 between the Tetron thread as a polymer insulating thread and the acetate thread for melt adhesion. The ratio of 3:1 may refer to the total thickness of the combined threads in addition to the number of threads. The winding pitch of the thread-like fiber 108 is preferably in the range of, for example, 1.5 mm to 3.5 mm. If the thread-like fiber 108 is made of a melting material, if the winding pitch is too wide, the adhesion of the abutting portion of the Litz wire will decrease, leading to a decrease in the shape retention at the separated portion. Therefore, the winding pitch of the thread-like fiber 108 is preferably in the above range.

The melting point of the tetron thread is, for example, 250°C to 255°C, and the melting point of the acetate thread is, for example, about 230°C. Therefore, when using these thread-like fibers 108 without melting them, it is preferable to use a common insulation 103 with a melting point lower than that of the thread-like fibers 108. This makes it possible to prevent the thread-like fibers 108 from melting when covering the common insulation 103. It is preferable to use, for example, polyethylene or polyvinyl chloride as the material for the common insulation 103. This makes it possible to maintain the shape of the litz wire 101 by maintaining the thread-like fibers 108 even after the common insulation 103 is peeled off from the litz wire 101. Therefore, it is possible to prevent the litz wire 101 from becoming flattened or coming apart when forming the coil 12.

Even if the thread-like fiber 108 melts due to the heat treatment of the common insulation 103, it is possible to peel off the common insulation 103 as long as the common insulation 103 and the melted thread-like fiber 108 are not bonded. When the thread-like fiber 108 melts due to the heat treatment of the common insulation 103, a fiber layer is formed on the surface of the litz wire 101. Therefore, after the common insulation 103 is peeled off, the litz wire 101 is in a state in which the fiber layer is fixed. By fixing the fiber layer to the litz wire 101, the coil 12 after the common insulation 103 is peeled off can obtain rigidity. Therefore, the coil shape is maintained when the coil 12 is handled alone (during handling). Therefore, it is not necessary to use a substrate having a groove with a gap formed therein as the support substrate 30.

Although one embodiment of the present invention has been described above with reference to the drawings, the present invention is not limited to the above embodiment and can be modified as appropriate without departing from the spirit of the present invention. For example, a product in which a person skilled in the art appropriately adds, deletes, or modifies components based on the manufacturing method for a contactless power supply coil of this embodiment is also included in the scope of the present invention as long as it satisfies the gist of the present invention. Furthermore, the above-mentioned embodiments can be appropriately combined as long as there are no mutual contradictions, and technical matters common to each embodiment are included in each embodiment even if not explicitly stated.

Even if there are other effects and advantages different from those brought about by the aspects of each of the above-mentioned embodiments, if they are clear from the description in this specification or can be easily predicted by a person skilled in the art, they are naturally understood to be brought about by the present invention.

10: coil for contactless power supply, 12: coil, 14: cable, 16: cable, 22: terminal, 22a: crimping portion, 22b: fixing portion, 24: terminal, 24a: crimping portion, 24b: fixing portion, 30: supporting substrate, 32: area, 101, 101A: litz wire, 103: common insulation, 107: strand, 107a: conductor, 107b: insulating coating, 108: thread-like fiber, 109: bundle, 112: notch

Claims (6)

forming a cut in the common insulation in a circumferential direction of the conductive wire at a location a first predetermined length from one end of the conductive wire having the common insulation;
A method for manufacturing a coil for contactless power supply, comprising sequentially repeating an operation of stripping off the common insulation from the cut portion to the other end over a second predetermined length, and an operation of placing the current-carrying wire from which the common insulation has been stripped in an area where a coil is to be placed, thereby forming a coil from the current-carrying wire from which the common insulation has been stripped. The method for manufacturing a coil for contactless power supply according to claim 1, wherein the first predetermined length is longer than the second predetermined length. The method for manufacturing a coil for contactless power supply according to claim 1, wherein the common insulating material is a heat-resistant polyolefin, polyethylene, vinyl chloride, fluorine-based resin, polyurethane resin, polyester resin, polyimide resin, or polyamide resin. The method for manufacturing a coil for contactless power supply according to claim 1, further comprising the step of crimping a terminal to one end of the common insulated current-carrying wire after forming the coil. The method for manufacturing a coil for contactless power supply according to claim 1, in which a filamentous fiber or a fiber layer is provided between the current-carrying wire and the common insulation. The method for manufacturing a coil for contactless power supply according to claim 1 , wherein the conductive wire is a Litz wire formed by twisting together a plurality of conductor wires each having an insulating coating applied to an outer circumferential surface thereof.

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