JP2006100077A - Wire rod for winding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wire rod for winding wherein loss due to an eddy current can be reduced and which is suitable for use with large current. <P>SOLUTION: This wire rod for winding has a conductor insulation coating 200 outside of a conductor 100. A conductor 100 is formed in one conductor 100 with a prescribed cross-section by combining a plurality of divided element wires 100A, 100B. Each divided element wire 100A, 100B comprises a conductor core wire 110A, 110B and a core wire insulation coating (oxide films 120A, 120B) covering the conductor core wire 110A, 110B. By constituting the conductor 100 the plurality of divided element wires 100A, 100B and forming the core wire insulation coating on each divided element wire 100A, 100B, between each divided element wire is electrically insulated to suppress a large eddy current from occurring in a conductor cross-section. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wire for winding and a method for manufacturing the wire for winding. In particular, the present invention relates to a wire for winding suitable for winding of electromagnetic parts such as a motor coil.

  As a motor coil, a wire for winding in which an insulating film such as polyamideimide is formed on a conductor made of copper or the like is known (for example, Patent Document 1). Such a wire for winding constitutes a coil by being wound around an iron core (core) constituting a stator or rotor of a motor.

  On the other hand, in recent years, with the progress of development of electric vehicles and hybrid vehicles, higher output motors have been demanded. One means for increasing the output of the motor is to increase the value of the current flowing through the motor coil.

  More specifically, it is conceivable to allow a large current to flow using a wire rod for winding having a large cross-sectional area.

JP 2002-15624 A

  However, the winding wire having a large cross-sectional area has a problem that eddy current loss occurs because no countermeasure is taken against eddy current.

  If the cross-sectional area of the conductor of the wire for winding is increased, the eddy current is increased, and the eddy current loss is accordingly increased.

  Here, if a twisted wire in which a plurality of insulated wires are twisted together is used as a wire for winding and the diameter of the twisted wire is the same as that of the wire for winding having a large cross-sectional area, the cross section of the conductor is the number of insulated wires. This is effective as a measure against eddy currents. However, in the case of a stranded wire, a space is formed between the insulated wires compared to a single wire having a large cross-sectional area, and the insulation film is doubled between adjacent insulated wires. Will drop.

  On the other hand, simply dividing the conductor cross section into a plurality of regions does not provide countermeasures against eddy currents because insulation is not provided between the divided regions.

  Accordingly, a main object of the present invention is to provide a wire for winding which can reduce loss due to eddy current and is suitable for use with a large current. Another object of the present invention is to provide a method for manufacturing such a wire for winding.

  The present invention achieves the above object by dividing a cross section of a conductor having an insulating coating into a plurality of divided strands.

  The wire for winding of the present invention is a wire for winding having a conductor insulating coating on the outside of the conductor, and the conductor is formed into one conductor having a predetermined cross section by combining a plurality of split strands, Each divided element wire is composed of a conductor core wire and a core wire insulating film covering the conductor core wire.

  The conductor is composed of a plurality of split strands, and a core wire insulation film is formed on each split strand to electrically insulate the split strands and suppress the generation of large eddy currents in the conductor cross section. be able to. That is, it is possible to divide the eddy current into smaller ones for each divided element wire and reduce eddy current loss.

  On the other hand, the manufacturing method of the wire material for winding of the present invention comprises a step of preparing a plurality of conductor core wires, a step of forming a core wire insulating film on each conductor core wire to form a split strand, and a plurality of split strands. It has the process of combining and making a conductor of predetermined cross-sectional shape, and forming a conductor insulating film on the outside of the conductor.

  According to this method, since a plurality of split strands are prepared in advance and then combined with a conductor having a predetermined cross section, a conductor having a predetermined cross section is formed by combining a plurality of strands and performing plastic working such as wire drawing. There is no need to For this reason, when the conductor is used, the core wire insulating film is not damaged.

  Hereinafter, the present invention will be described in more detail.

  The wire for winding of the present invention has a conductor and a conductor insulating coating formed on the outside of the conductor. Among these, the conductor is formed in a predetermined cross section by collecting a plurality of split strands.

  A split strand is a strand corresponding to one region when a cross section of a conductor is divided into a plurality of regions by a core insulating film. Each split strand is composed of a conductor core wire and a core wire insulating film.

  As the material of the conductor core wire, various materials can be used as long as they are conductive wires. Those with a proven track record as windings for motors, transformers, reactors, etc. are preferred. For example, copper, copper alloy, aluminum, aluminum alloy, copper-covered aluminum, or copper-covered aluminum alloy can be used.

  The cross-sectional shape of the conductor core wire is a shape that can be combined to form a conductor having a predetermined cross-sectional shape. In particular, a cross-sectional shape that constitutes a conductor having a predetermined cross-section by being combined with adjacent conductor core wires by surface contact is preferable. Adjacent conductor core wires are in surface contact with each other, thereby eliminating the generation of voids between the conductor core wires and improving the space factor when used as a coil. In such a conductor core wire that can be brought into surface contact, at least one conductor core wire may be non-circular. Specifically, a conductor core wire having a fan-shaped cross section with a central angle of 90 ° is prepared, and a conductor having a circular cross section is formed using four of them, or four conductor core wires having a rectangular cross section are used. It is conceivable that the conductor has a rectangular cross section.

  A typical method for forming the conductor core wire is wire drawing. For example, a cross-sectional shape of a conductor core wire that can be combined into a conductor having a predetermined cross-sectional shape is determined, and wire drawing is performed using a modified die corresponding to the shape of the conductor core wire.

  On the other hand, the core wire insulating coating is a coating that is formed on each conductor core wire and has a function of dividing eddy currents between the conductor core wires. This film only needs to ensure the insulation performance necessary for eddy current division.

An oxide film is suitable for the material of the core wire insulating film. For example, when the conductor core wire is made of copper, a cuprous oxide (Cu ₂ O) film may be formed on the core wire and used as a core wire insulating coating. The insulating property of the cuprous oxide film is not necessarily high, but it can be used to divide the eddy current.

  The thickness of the core wire insulating film is set to a thickness that provides an insulating characteristic that can divide the eddy current. In general, if the material has a resistance equal to or higher than that of an oxide film, the above insulating characteristics can be obtained if the thickness is 1 μm or more. However, a thinner core insulation film is preferable because the space factor when used as a coil can be increased. Accordingly, it is desirable that the thickness of the core wire insulating coating be about 10 μm or less.

  The method for forming the core insulating film may be typically performed by heat-treating the conductor core wire when the oxide film is formed. For example, when processing in air | atmosphere, an oxide film can be formed by hold | maintaining at 700-800 degreeC for 5 to 60 second, and then rapidly cooling to 300 degrees C or less using refrigerant | coolants, such as water.

  A plurality of the above-described split strands are prepared and combined to constitute a conductor. That is, instead of plastically processing a conductor having a predetermined cross section after combining a plurality of strands, a split strand having a predetermined cross section is obtained in advance, and a conductor having a predetermined cross section is formed by combining these split strands. Therefore, a conductor can be formed without performing plastic working such as wire drawing after the combination of the strands, and damage to the core insulating film due to plastic working can be avoided. Moreover, the method of a combination may just focus a several division | segmentation strand, and may add twist after converging.

  If a conductor is formed by this combination, the divided strands may be integrated with an anti-scattering material. By constituting each divided strand integrally, it is possible to prevent the conductor from collapsing during winding. Of course, if the anti-scattering material is provided, the function of reinforcing the conductor can also be realized. As a material for the anti-scattering material, a metal material is preferable from the viewpoint of improving the space factor. Examples of the method for forming the anti-scattering material include sleeve formation and tape winding. For example, a metal sleeve may be formed on the conductor by extrusion or the like, or a metal tape may be spirally wound on the conductor to form a scattering prevention material. Needless to say, when the split strands are combined, if the strands are not separated, it is not necessary to provide the anti-scattering material.

  Conductor insulation coating is applied to the conductor composed of the split strands. This conductor insulating film is for ensuring insulation between adjacent turns when the wire for winding is used as a coil. As a material for the conductor insulating film, polyester, polyesterimide, polyamideimide, polyimide, or the like can be used. This method for forming a conductor insulating film is typically performed by thinly applying an insulating paint to a conductor and passing the conductor through a conductor insulating film baking furnace. When the anti-scattering material is used, a conductor insulating film may be formed on the anti-scattering material.

  The wire for winding of the present invention can be suitably used as a winding for a motor, a transformer, a reactor, or the like. In particular, it can be suitably used as a motor coil of a traveling motor mounted on an electric vehicle or a hybrid vehicle that is required to cope with a larger current in recent years.

  As described above, according to the wire for winding of the present invention, since the conductor itself is divided into a plurality of regions in the cross section by the divided strands on which the core insulating film is formed, a large eddy current is generated in the conductor cross section. It is possible to suppress the eddy current loss.

  In addition, according to the method for manufacturing a wire for a winding of the present invention, since a plurality of split strands are prepared in advance and then combined with a conductor having a predetermined cross section, the plurality of strands are combined and then plasticity such as wire drawing is performed. It is not necessary to process the conductor into a predetermined cross-sectional shape. For this reason, when the conductor is used, the core wire insulating film is not damaged.

  Embodiments of the present invention will be described below.

(Example 1: Wire having a circular cross section)
FIG. 1 is a cross-sectional view of the wire for winding of the present invention. As shown in this figure, the wire of the present invention has a conductor 100 and a conductor insulating coating 200 formed on the outside of the conductor. Among these, the conductor 100 is configured in a circular cross section by combining a plurality of split strands. Furthermore, in this example, the anti-scattering material 300 is provided between the conductor and the conductor insulating film.

The conductor 100 constituting this wire is composed of one circular segmented strand 100A and eight fan-shaped segmented strands 100B. Each of the split strands 100A and 100B has a configuration in which oxide films 120A and 120B are formed on the conductor core wires 110A and 110B. Here, copper was used for the conductor core wires 110A and 110B, and a cuprous oxide (Cu ₂ O) film was used for the oxide films 120A and 120B.

  The conductor core wires 110A and 110B are obtained by wire drawing. That is, the circular segmented wire 100A is obtained by drawing with a circular die, and the sector-shaped segmented wire 100B is obtained by drawing using a modified die having a fan-shaped die hole. This fan-shaped segmented wire 100B has a cross-sectional shape in which both ends of a concentric short arc and a long arc are connected by a straight line, and the bending diameter of the short arc matches the bending diameter of the outer peripheral surface of the circular segmented strand 100A. It is a size. The oxide films 120A and 120B have a thickness of 1 μm by holding the drawn conductor core wires 110A and 110B at 700 ° C. for 10 seconds and rapidly cooling to 300 ° C. or lower.

  After obtaining the divided strands 100A and 100B as described above, the circular divided strand 100A is arranged at the center, and the eight fan-shaped divided strands 100B are arranged so as to surround the circular divided strand 100A. A conductor having a circular cross section is formed.

  When the conductor 100 is formed, the anti-scattering material 300 is provided on the conductor 100. Here, the anti-scattering material 300 is formed by winding an aluminum metal tape around the conductor 100 in a spiral shape. By providing the anti-scattering material 300, it is possible to prevent the conductor 100 from being scattered in the subsequent handling of the conductor 100.

  Subsequently, the conductor insulating film 200 is formed on the anti-scattering material 300. Here, the insulating coating 200 of polyamideimide was thinly applied on the conductor, and the conductor was passed through a conductor insulating coating baking furnace to form the conductor insulating coating 200. The thickness of the formed conductor insulating film 200 is 36 μm.

  According to the above wire rods for winding, since the conductor cross section is divided for each split strand 100A, 100B by the oxide films 120A, 120B, generation of large eddy currents can be suppressed and eddy current loss can be reduced. Can do. Moreover, since the large cross-sectional area is ensured as the whole conductor, it can respond to use with a large current.

(Example 2: circular cross-section conductor)
In the first embodiment, the split strands having two kinds of cross-sectional shapes, the circular split strand and the sector split strand, are used. However, the conductor may be configured by split strands having the same cross-sectional shape.

  FIG. 2 is a conductor cross-sectional view of the wire of the present invention composed only of sector-shaped divided wires. In the conductor 100, a conductor 100 having a circular cross section is configured by combining four divided strands 100C having a sector shape with a central angle of 90 °. In each of the segmented wires, the oxide film 120C is formed on the conductor core wire 110C as in the first embodiment. Further, although not shown, the point that a conductor insulating film is formed outside the conductor 100 is the same as that of the first embodiment.

  As shown in this figure, it is possible to appropriately change the number of conductor divisions (number of divided strands) and the cross-sectional shape of the divided strands in accordance with the required eddy current countermeasures. If the conductor of this example is used, the wire rod for winding which can subdivide an eddy current without using a circular division | segmentation strand can be obtained.

(Example 3: rectangular cross-section conductor)
Next, the wire for winding of the present invention using a conductor having a rectangular cross section will be described. FIG. 3 is a cross-sectional view of a conductor having a rectangular cross section in the wire of the present invention.

  As shown in FIG. 3 (A), the conductor 100 is configured by dividing rectangular strands 100D in parallel in the horizontal direction. Each split strand 100D is drawn with an odd-shaped die having a rectangular die hole to obtain a conductor core wire 110D, and each conductor core wire 110D is subjected to the same heat treatment as in Example 1 to form an oxide film 120D. Yes. Then, the conductor 100 is configured by paralleling the four split strands 100D. A conductor insulating film (not shown) is formed on the obtained conductor 100 in the same manner as in Example 1. An anti-separation material may be provided as necessary.

  In this embodiment, the divided strands 100D are arranged in parallel only in the horizontal direction, but the divided strands 100D may be arranged in parallel in both the horizontal direction and the vertical direction to form a conductor having the configuration shown in FIG.

  If a wire for winding using such a rectangular cross-section conductor is used, when the wire is aligned and wound on an iron core, the wires are adjacent to each other in surface contact and no gap is formed between the wires. Further improvement of the space factor can be realized.

  The wire for winding of the present invention can be suitably used as a winding for a motor, a transformer, a reactor, or the like. In particular, it can be suitably used as a motor coil of a traveling motor mounted on an electric vehicle or a hybrid vehicle. Moreover, the manufacturing method of the wire for winding of the present invention is used in the field of manufacturing the wire for winding of the present invention.

It is sectional drawing of the wire material for windings of this invention in Example 1. FIG. It is sectional drawing of the conductor of the wire material for windings of this invention in Example 2. FIG. It is sectional drawing of the conductor of the wire material for windings of this invention in Example 3.

Explanation of symbols

100 conductor 100A Circular segmented wire 100B, 100C Fan segmented strand
100D rectangular segment wire 110A, 110B, 110C, 110D conductor core wire
120A, 120B, 120C, 120D oxide film
200 Conductor insulation coating
300 Anti-scattering material

Claims (4)

A wire rod for winding having a conductor insulating coating on the outside of the conductor,
The conductor is formed into one conductor having a predetermined cross section by combining a plurality of split strands,
Each of the split strands is composed of a conductor core wire and a core wire insulating film covering the conductor core wire.   The wire for winding according to claim 1, wherein the core wire insulating film is an oxide film.   The wire for winding according to claim 1, wherein the split strand includes a non-circular cross-sectional shape. Preparing a plurality of conductor core wires,
Forming a core wire insulation film on each conductor core wire to form a split strand;
A step of combining a plurality of split strands into a conductor having a predetermined cross-sectional shape;
And a step of forming a conductor insulating film on the outside of the conductor.

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