Method for manufacturing conductive member

Abstract

To secure an insulation property of a conductive member, while suppressing an insulative film of the conductive member as a whole from getting thicker.SOLUTION: A conductive member manufacturing method has a step of coating a conductive body with an insulative film (an insulative coated film), where the step has a first step of preparing a conductive body having a bent part and a second step in which a thin film-like insulative film is floated on a liquid level of liquid and the conductive body is arranged upper with respect to the insulative film, then the insulative film is closely attached to the conductive body by pressure of liquid while making the conductive body move down into the liquid so as to coat the conductive body with the insulative film, and the conductive body coated with the insulative film is moved up from the liquid.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a method for producing a conductive member. [Background technology]

[0002] Conventionally, multiple U-shaped segment coils for constituting the stator coil of a rotating electric machine have been proposed, each formed from a rectangular wire whose outer periphery of the conductor is covered with an insulating film (insulating coating) (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 003559 Summary of the Invention [Problem to be solved by the invention]

[0004] When forming a U-shaped conductor segment by bending a rectangular wire whose outer circumference is covered with an insulating film (insulating coating), the insulating film on the outer circumference of the bent part may become thin. If it is desired to ensure the thickness of the insulating film in this part, it is necessary to make the insulating film thicker overall, which leads to a decrease in the space factor.

[0005] The main object of the method for producing a conductive member of the present invention is to ensure the insulating properties of the conductive member while preventing the insulating film of the entire conductive member from becoming thick. [Means for solving the problem]

[0006] The method for producing a conductive member of the present invention employs the following measures to achieve the above-mentioned main object.

[0007] The method for producing a conductive member of the present invention includes the steps of: A method for producing a conductive member, comprising a step of covering a conductor with an insulating film, The process comprises: A first step of preparing the conductor having a bent portion; a second step of floating the insulating film in a thin film form on the surface of a liquid and arranging the conductor above the insulating film, lowering the conductor into the liquid while causing the insulating film to adhere to the conductor by the pressure of the liquid, thereby covering the conductor with the insulating film, and raising the conductor covered with the insulating film from the liquid. The gist of the present invention is as follows.

[0008] The method for producing a conductive member of the present invention includes a step of covering a conductor with an insulating film (insulating coating), and the step includes a first step of preparing a conductor having a bent portion, and a second step of floating a thin insulating film on the surface of a liquid and arranging the conductor above the insulating film, lowering the conductor into the liquid while causing the insulating film to adhere to the conductor by the pressure of the liquid, thereby covering the conductor with the insulating film, and then raising the conductor covered with the insulating film from the liquid. In this way, it is possible to prevent the insulating film on the outer periphery of the bent portion of the conductor from becoming thin, compared to a case in which the conductor is covered with an insulating film before forming the bent portion. As a result, it is possible to ensure the insulation of the conductive member while preventing the insulating film of the entire conductive member from becoming thick (lowering the space factor).

[0009] In the method for producing a conductive member of the present invention, the second step may comprise removing the liquid from the insulating film after the conductor covered with the insulating film is raised from the liquid. Methods for removing the liquid from the insulating film include rotating the conductor covered with the insulating film and blowing air.

[0010] In the method for producing a conductive member of the present invention, the second step may be performed a number of times, so that the thickness of the insulating film can be adjusted by the number of times the second step is performed.

[0011] In the method for manufacturing the conductive member of the present invention, the second step may be performed at least once for the entire conductive body and then at least once for a part of the conductive body. By doing so, the thickness of the insulating film can be adjusted for each part of the conductive member.

Brief Description of the Drawings

[0012] [Figure 1] FIG. 8 is a configuration diagram showing an outline of the configuration of the stator 10 in which a conductive member manufactured by the method for manufacturing a conductive member as an embodiment of the present invention is used. [Diagram 2] FIG. 11 is a configuration diagram showing an outline of the configuration of the segment coil 13. [Diagram 3] FIG. 14 is a process diagram showing each process of the method for manufacturing the segment coil 13. [Figure 4] FIG. 17 is an explanatory diagram of step S110.

Embodiments for Carrying Out the Invention

[0013] Next, embodiments for carrying out the present invention will be described using examples.

Examples

[0014] FIG. 1 is a configuration diagram showing an outline of the configuration of the stator 10 in which a conductive member manufactured by the method for manufacturing a conductive member as an embodiment of the present invention is used. The stator 10, together with a rotor (not shown), constitutes a three-phase AC motor (synchronous motor or induction motor) used in an electric vehicle or a hybrid vehicle. This stator 10 includes a stator core 11 and a plurality of stator coils 12. As the conductive member of the embodiment, the segment coil 13 described later used in the stator coil 12 corresponds to it.

[0015] The stator core 11 is formed by stacking a plurality of magnetic steel sheets formed into an annular shape by, for example, pressing and connecting them in the stacking direction by crimping or the like. The stator core 11 may be formed integrally by, for example, pressure-molding and sintering ferromagnetic powder. The stator core 11 has a central hole in which a rotor is disposed, a plurality of teeth portions (not shown) that extend radially from an annular outer periphery (yoke portion) toward the axis (center of the stator core 11) and are adjacent to each other at regular intervals in the circumferential direction, and a plurality of slots (not shown) formed between the adjacent teeth portions. The plurality of slots each extend radially of the stator core 11, are arranged at regular intervals in the circumferential direction, and open at the central hole.

[0016] The multiple stator coils 12 have coils for each phase (U-phase, V-phase, W-phase), and each stator coil 12 is formed by electrically connecting multiple segment coils (conductive members) 13 inserted into the stator core 11. As shown in FIG. 2, each segment coil 13 is a substantially U-shaped rectangular wire in which the surface of a conductor 17 is covered with an insulating film (insulating coating) 18. The conductor 17 is made of, for example, copper. The insulating film 18 is made of, for example, a fluororesin with a low dielectric constant, polyimide, polyetherimide, polyamide, or the like with a low dielectric constant and high self-adhesiveness. Each segment coil 13 has a base 14 and a pair (two) of legs 16 extending from both ends of the base 14 to the same side via bent parts 15. At the tip of each leg 16, the insulating film 18 is removed to expose the conductor 17.

[0017] The two legs 16 of each segment coil 13 are inserted into different slots of the stator core 11. The tip of the leg 16 of each segment coil 13 protruding from one end face (upper end face in FIG. 1) of the stator core 11 is electrically joined to the tip of the leg 16 of the corresponding other segment coil 13 by welding. In this way, the multiple stator coils 12 are wound around the stator core 11. Also, a coil end portion 12a is formed on one end side (upper end side in FIG. 1) of the stator core 11 in the axial direction, and an annular coil end portion 12b is formed on the other end side (lower end side in FIG. 1). The coil end portions 12a and 12b are each formed by multiple stator coils 12, i.e., multiple segment coils 13, and protrude outward from the end face of the stator core 11 in the axial direction.

[0018] Next, a method for manufacturing the U-shaped segment coil 13 will be described. Fig. 3 is a process diagram showing each step of the method for manufacturing the segment coil 13. In the method for manufacturing the segment coil 13, first, a U-shaped conductor 17 is prepared (step S100). Here, the U-shaped conductor 17 can be formed, for example, by bending a straight conductor 17 using a forming die. In the following description, each part of the conductor 17 and the intermediate member 13a (both of which are U-shaped) described below will be referred to as the base 14, the bent part 15, and the leg part 16, just like the segment coil 13.

[0019] Next, the entire conductor 17 is covered with an insulating film 18 to form an intermediate member 13a (step S110), and the insulating film 18 is removed from the tips of the pair (two) legs 16 of the intermediate member 13a (step S120) to complete the segment coil 13.

[0020] 4 is an explanatory diagram of step S110. In step S110, first, as shown in FIG. 3(A), a thin-film insulating film 18 (insulating material) is floated on the liquid surface of the liquid 32 stored in the storage section 30, and the conductor 17 is arranged above the center of the insulating film 18 so that its base 14 is lower (on the insulating film 18 side) than the pair of legs 16. Next, as shown in FIG. 3(B) and FIG. 3(C), the conductor 17 is lowered to make the entire conductor 17 enter the liquid 32, and the insulating film 18 is brought into close contact with the entire conductor 17 by the pressure of the liquid 32, thereby covering the entire conductor 17 with the insulating film 18, and forming the intermediate member 13a. Then, as shown in FIG. 3(D), the intermediate member 13a is raised from the liquid 32, and as shown in FIG. 3(E), the intermediate member 13a is rotated to remove the liquid 32 from the outer surface of the insulating film 18 of the intermediate member 13a.

[0021] Here, for example, water or hydraulic oil (ATF) is used as the liquid 32. As described above, for example, low dielectric constant fluororesin, low dielectric constant and high self-adhesive polyimide, polyetherimide, polyamide, etc. are used as the material of the insulating film 18. If the specific gravity of the insulating film 18 is greater than that of the liquid 32, it is possible to support the outer edge of the insulating film 18 with a support member or the like in order to prevent the insulating film 18 from sinking. Also, when the entire conductor 17 is covered with the insulating film 18, it is possible to float the insulating film 18 on the surface of the liquid 32 by forming the insulating film 18 into a bowl shape with a center recessed below the outer edge in order to prevent the liquid 32 from entering between the conductor 17 and the insulating film 18.

[0022] In this way, by manufacturing the U-shaped segment coil 13 including the step S110 of covering the entire U-shaped conductor 17 with the insulating film 18, it is possible to suppress the insulating film 18 on the outer periphery side of the bent portion 15 (see FIG. 2) of the segment coil 13 from becoming thin, compared to the case where the entire linear conductor 17 is covered with the insulating film 18 and then formed into a U-shape. As a result, it is possible to ensure the insulation of the segment coil 13 while suppressing the insulating film 18 of the entire segment coil 13 from becoming thick (reducing the space factor). Moreover, after the intermediate member 13a formed by covering the entire conductor 17 with the insulating film 18 in the liquid 32 is raised from the liquid 32, the intermediate member 13a is rotated to remove the liquid 32 from the outer surface of the insulating film 18 of the intermediate member 13a, and the liquid 32 can be removed from the insulating film 18 without heating the conductor 17 or the insulating film 18.

[0023] In the manufacturing method of the segment coil 13 of the embodiment described above, the U-shaped segment coil 13 is manufactured by including a process of covering the entire U-shaped conductor 17 with an insulating film (insulating coating) 18. In this process, a thin-film insulating film 18 (insulating material) is floated on the liquid surface of the liquid 32 stored in the storage section 30, and the conductor 17 is placed above the insulating film 18. The conductor 17 is lowered to make the entire conductor 17 enter the liquid 32, and the insulating film 18 is adhered to the entire conductor 17 by the pressure of the liquid 32, so that the entire conductor 17 is covered with the insulating film 18. This makes it possible to prevent the insulating film 18 on the outer periphery side of the bent portion 15 of the segment coil 13 from becoming thin. As a result, it is possible to ensure the insulation of the segment coil 13 while preventing the insulating film 18 of the entire segment coil 13 from becoming thick (the space factor from becoming low).

[0024] In the manufacturing method of the segment coil 13 of the embodiment, step S110 of covering the entire conductor 17 with the insulating film 18 is performed only once. However, this step S110 may be performed multiple times. The thickness of the insulating film 18 can be adjusted by the number of times step S110 is performed.

[0025] In the manufacturing method of the segment coil 13 of the embodiment, step S110 of covering the entire conductor 17 with the insulating film 18 is performed only once. However, after performing step S110 at least once for the entire conductor 17, a step similar to step S110 may be performed at least once for a portion of the conductor 17 (intermediate member 13a). In this way, the thickness of the insulating film 18 can be adjusted for each portion of the intermediate member 13a.

[0026] In the manufacturing method of the segment coil 13 of the embodiment, the intermediate member 13a formed by covering the entire conductor 17 with the insulating film 18 in the liquid 32 is raised from the liquid 32, and then the intermediate member 13a is rotated to remove the liquid 32 from the insulating film 18 of the intermediate member 13a. However, instead of this, the liquid 32 may be removed from the insulating film 18 by blowing air onto the intermediate member 13a. Also, the intermediate member 13a may be left as it is (naturally dried).

[0027] In the embodiment, a method for manufacturing a U-shaped segment coil 13 was described as a method for manufacturing a conductive member. However, the conductive member may be any conductive member having a bent portion and a surface of the conductor covered with an insulating film, and may be, for example, a bus bar or a connection terminal used in an electric motor or a power storage device, in addition to the segment coil 13. The conductor and insulating film may be appropriately selected according to the conductive member. In addition to the above-mentioned copper, the conductor may be, for example, gold, silver, aluminum, conductive resin, etc. In addition to the above-mentioned fluorine-based resin, polyimide, polyetherimide, and polyamide, the insulating film may be, for example, acrylic, wood, paper, concrete, etc.

[0028] The correspondence between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problems will be explained. In the embodiment, the conductor 17 corresponds to the "conductor", the insulating film 18 corresponds to the "insulating film", and the segment coil 13 corresponds to the "conductive member".

[0029] The correspondence between the main elements of the Examples and the main elements of the invention described in the Summary of the Problem column does not limit the elements of the invention described in the Summary of the Problem column, since the Examples are examples for specifically explaining the mode for implementing the invention described in the Summary of the Problem column. In other words, the interpretation of the invention described in the Summary of the Problem column should be based on the description in that column, and the Examples are merely a specific example of the invention described in the Summary of the Problem column.

[0030] Although the form for carrying out the present invention has been described above using examples, the present invention is not limited to these examples in any way, and it goes without saying that the present invention can be carried out in various forms without departing from the scope of the gist of the present invention. [Industrial Applicability]

[0031] The present invention can be used in the conductive member manufacturing industry and the like. [Explanation of symbols]

[0032] 10 stator, 11 stator core, 12 stator coil, 12a, 12b coil end portion, 13 segment coil, 13a intermediate member, 14 base portion, 15 bent portion, 16 leg portion, 17 conductor, 18 insulating film, 30 storage portion, 32 liquid.

Claims

1. A method for producing a conductive member, comprising a step of covering a conductor with an insulating film, The process comprises: A first step of preparing the conductor having a bent portion; a second step of floating the thin-film insulating film on the surface of the liquid in a bowl shape with the center recessed lower than the outer edge, and arranging the conductor above the insulating film, lowering the conductor into the liquid while causing the insulating film to adhere to the conductor by the pressure of the liquid, thereby covering the conductor with the insulating film, and raising the conductor covered with the insulating film from the liquid. A method for manufacturing a conductive member.

2. A method for producing a conductive member according to claim 1, comprising the steps of: The second step includes removing the liquid from the insulating film after lifting the conductor covered with the insulating film from the liquid. A method for manufacturing a conductive member.

3. A method for producing the conductive member according to claim 1 or 2, comprising the steps of: The second step is carried out multiple times. A method for manufacturing a conductive member.

4. A method for producing the conductive member according to claim 1 or 2, comprising the steps of: The second step is performed at least once for the entire conductor, and then at least once for a portion of the conductor. A method for manufacturing a conductive member.

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