JP7679745B2 - Method for manufacturing conductive member - Google Patents

Description

The present invention relates to a method for manufacturing a conductive member.

Conventionally, multiple U-shaped segment coils for constructing the stator coil of a rotating electric machine have been proposed, each made of rectangular wire with the outer periphery of the conductor covered with an insulating film (insulating coating) (see, for example, Patent Document 1).

International Publication No. 2019/003559

When forming a U-shaped segment conductor by bending a rectangular wire whose outer periphery is covered with an insulating film (insulating coating), the insulating film on the outer periphery of the bent part may become thin. 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.

The main purpose of the method for manufacturing a conductive member of the present invention is to ensure the insulation of the conductive member while preventing the insulating film of the entire conductive member from becoming thick.

The manufacturing method of the conductive member of the present invention employs the following measures to achieve the above-mentioned main objective.

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 the 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.

The method for manufacturing 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 the liquid pressure causes the insulating film to adhere to the conductor, thereby covering the conductor with the insulating film, and then raising the conductor covered with the insulating film from the liquid. By doing this, it is possible to prevent the insulating film on the outer periphery of the bent portion of the conductor from becoming thin, compared to when 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).

In the method for manufacturing a conductive member of the present invention, the second step may involve 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.

In the method for manufacturing a conductive member of the present invention, the second step may be performed multiple times. The thickness of the insulating film can be adjusted by the number of times the second step is performed.

In the method for manufacturing a conductive member of the present invention, the second step may be performed at least once for the entire conductor, and then at least once for a portion of the conductor. In this way, the thickness of the insulating film can be adjusted for each portion of the conductive member.

1 is a diagram showing an outline of the configuration of a stator 10 using a conductive member manufactured by a conductive member manufacturing method according to one embodiment of the present invention; A diagram showing the outline of the configuration of a segment coil 13. A process diagram showing each step of a manufacturing method for segment coil 13. FIG. 11 is an explanatory diagram of step S110.

Next, we will explain how to implement the present invention using examples.

Figure 1 is a schematic diagram showing the configuration of a stator 10 that uses a conductive member manufactured by a conductive member manufacturing method according to one embodiment of the present invention. The stator 10, together with a rotor (not shown), constitutes a three-phase AC motor (synchronous motor or induction motor) used in electric vehicles and hybrid vehicles. This stator 10 includes a stator core 11 and a plurality of stator coils 12. The conductive member of the embodiment corresponds to the segment coils 13 described below that are used in the stator coils 12.

The stator core 11 is formed, for example, by stacking multiple electromagnetic steel sheets formed into a circular ring shape by pressing and connecting them in the stacking direction by crimping or the like. The stator core 11 may also be formed as a single piece by, for example, press-molding and sintering ferromagnetic powder. The stator core 11 has a central hole in which a rotor is disposed, multiple teeth portions (not shown) that extend radially from the 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 multiple slots (not shown) formed between the adjacent teeth portions. The multiple slots each extend radially of the stator core 11, are arranged at regular intervals in the circumferential direction, and open at the central hole.

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 with the surface of the conductor 17 covered with an insulating film (insulating coating) 18. The material of the conductor 17 is, for example, copper. The material of the insulating film 18 is, for example, a low-dielectric fluorine-based resin, a low-dielectric and highly self-adhesive polyimide, polyetherimide, polyamide, etc. 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 a bent portion 15. At the tip of each leg 16, the insulating film 18 is removed to expose the conductor 17.

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, multiple stator coils 12 are wound around the stator core 11. Also, a coil end portion 12a is formed at one end side (upper end side in FIG. 1) of the stator core 11 in the axial direction, and a ring-shaped coil end portion 12b is formed at 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 in the axial direction of the stator core 11.

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 the linear conductor 17 using a forming die. In the following description, each part of the conductor 17 and the intermediate member 13a (which will be described later) (both of which are U-shaped) will be referred to as the base 14, the bent part 15, and the leg part 16, just like the segment coil 13.

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

Figure 4 is an explanatory diagram of step S110. In step S110, first, as shown in Figure 3 (A), a thin-film insulating film 18 (insulating material) is floated on the surface of the liquid 32 stored in the storage section 30, and the conductor 17 is placed 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 Figures 3 (B) and 3 (C), the conductor 17 is lowered to make the entire conductor 17 enter the liquid 32, while 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 and an intermediate member 13a is formed. Then, as shown in Figure 3 (D), the intermediate member 13a is raised from the liquid 32, and as shown in Figure 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.

Here, for example, water or hydraulic oil (ATF) is used as the liquid 32. As described above, for example, low-dielectric fluororesin, low-dielectric and highly self-adhesive polyimide, polyetherimide, polyamide, etc. are used as the material for 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. In addition, when the entire conductor 17 is covered with the insulating film 18, in order to prevent the liquid 32 from entering between the conductor 17 and the insulating film 18, it is also 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 the center recessed below the outer edge.

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 prevent the insulating film 18 on the outer periphery of the bent portion 15 (see FIG. 2) of the segment coil 13 from becoming thin, compared to when 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 preventing 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.

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 of 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, the insulating film 18 of the entire segment coil 13 can be prevented from becoming thick (the space factor becomes low) while ensuring the insulation of the segment coil 13.

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.

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 on the entire conductor 17, a step similar to step S110 may be performed at least once on 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.

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. The intermediate member 13a may also be left as it is (naturally dried).

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 member that has a bent portion and whose surface is covered with an insulating film, and examples of the conductive member include bus bars and connection terminals used in electric motors and power storage devices in addition to the segment coil 13. The conductor and insulating film can be appropriately selected depending on the conductive member. Examples of the conductor include, in addition to the above-mentioned copper, for example, gold, silver, aluminum, conductive resin, etc. Examples of the insulating film include, in addition to the above-mentioned fluorine-based resin, polyimide, polyetherimide, and polyamide, for example, acrylic, wood, paper, concrete, etc.

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 problem 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".

The correspondence between the main elements of the Examples and the main elements of the invention described in the Means for Solving the Problem column does not limit the elements of the invention described in the Means for Solving the Problem column, since the Examples are examples for specifically explaining the form for implementing the invention described in the Means for Solving the Problem column. In other words, the interpretation of the invention described in the Means for Solving 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 Means for Solving the Problem column.

The above describes the form for carrying out the present invention using examples, but 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 invention.

This invention can be used in the conductive material manufacturing industry, etc.

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 (4)

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. 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. 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. 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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