JP2010124636A - Coil unit and stator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coil unit, or the like, having small size and suppressing the skin effect, while suppressing a circulating current. <P>SOLUTION: The coil unit 10 includes a first coil 10a, which is a small coil and a second coil 10b which is a large coil. The coil unit 10 is constituted by fitting small coils 10a, 10b sequentially from the inside. The winding directions of the first coil 10a and the second coil 10b are opposite to each other. The first and second coils 10a, 10b do not generate a circulating current because they are connected in series. Coil wire ends 11a, terminated on the same end of the respective coils 10a, 10b, are coupled with each other by a coupling member 10z. As a result, coupling process is simplified and the axial length is also shortened. Adverse effects due to the skin effect is suppressed as compared with the coil formed by edgewisely winding one straight-angle wire. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a coil unit used for a rotary motor, a linear motor, a generator, and the like, and a stator provided with the coil unit.

  Generally, a coil disposed in a motor, a generator, a reactor, a transformer, and the like is configured by winding a thin copper wire many times. In a motor stator, a coil in which a round wire having a substantially circular cross section is wound around a core or a tooth portion of a split core is widely used.

  On the other hand, a coil structure in which a flat coil called a flat wire is wound in an edgewise manner has been proposed recently. By winding the flat wire in an edgewise manner, the space factor and heat dissipation are improved as compared with a coil using a round wire. Further, since there is no crossover processing at the time of coil formation, there is also an advantage that the coil assembly process can be simplified.

On the other hand, when bending a rectangular wire, it is necessary to allow for a bending radius at least as large as the width of the rectangular wire. Therefore, the size of the coil may be excessive.
In general, it is known that when a high-frequency current flows through a conducting wire, a skin effect occurs in which the current is biased to the surface of the conducting wire.

Therefore, in order to eliminate the above-described problems of the rectangular wire, Patent Documents 1 and 2 propose the following coil structure.
The coil of Patent Document 1 incorporates a plurality of rectangular coil wires covered with an insulator like a single flat wire. The entire flat wire is wound in an edgewise shape.
The coil of Patent Document 2 uses a plurality of coil portions that are wound by bundling coil wires into divided rectangular wires. At that time, the diameter of each coil portion is gradually increased, and the respective coil portions are sequentially fitted concentrically.
JP 2005-327834 A JP 2005-209916 A

  The coil structures of Patent Documents 1 and 2 are so-called structures in which flat wires are subdivided. Therefore, the bending radius can be reduced and the size of the coil can be kept small. Further, the influence of the skin effect can be reduced by increasing the surface area of the coil.

  However, in the techniques of Patent Documents 1 and 2, since the lengths of the plurality of conductors wound on the upper and lower layers are different, there is also a difference in the resistance value. As a result, a voltage difference is generated with respect to the high-frequency current due to the resistance difference between the plurality of conductive wires connected to the common terminal, and a circulating current flows. This circulating current does not contribute to the output of the motor and becomes an invalid current.

  An object of the present invention is to provide a coil unit capable of suppressing the skin effect while suppressing a circulating current and a stator including the coil unit.

  The coil unit of the present invention is configured by sequentially fitting a plurality of coils having different radial sizes from the inside. Coil wires of two adjacent coils among the plurality of coils are wound in opposite directions. Each one coil wire end which terminates in the end face of the same side of each coil is connected. Examples of connection methods include welding, brazing, and twisting.

As a result, the plurality of coils are connected in series without canceling the magnetic field. Therefore, no circulating current is generated. And since one coil wire end which terminates in the end surface of the same side of two coils is connected, a connection process is also easy and an axial length can also be suppressed.
On the other hand, the other coil wire ends serving as external terminals are terminated at different end surfaces. If this other end face is on the yoke side when incorporated in the stator, the bus bar can be disposed on the yoke portion. Therefore, the axial length can be further reduced.
In addition, an adverse effect due to the skin effect can be suppressed as compared with a coil in which one flat wire is wound edgewise.

  The coil wire ends are preferably connected at a coil end portion. Thereby, the fall of a space factor can be suppressed.

A stator in which a plurality of coil units of the present invention are mounted on the same number of cores exhibits high convenience as parts such as a motor, generator, reactor, and transformer with a small loss. The stator may be a split stator or an integrated stator.
In that case, it is preferable that the other coil wire ends of the coil units are electrically connected to each other at the yoke portion of the core.

  According to the coil unit or the stator of the present invention, the skin effect can be suppressed with a small size while suppressing the circulating current.

(Embodiment 1)
-Structure of coil unit and stator-
FIG. 1 is a perspective view showing a state where each coil of the coil unit 10 according to Embodiment 1 is prepared. The coil unit 10 of the present embodiment includes a first coil 10a that is a small coil and a second coil 10b that is a large coil. Each of the first and second coils 10a and 10b is obtained by winding a rectangular wire 11 (coil wire) in an edgewise manner. In this embodiment, the number of turns of each coil 10a, 10b is the same. The coil wire ends 11a and 11b of each rectangular wire 11 are all facing upward at this stage.

  The flat wire 11 includes a copper wire 12 having a substantially rectangular cross section and a coating film 13 that covers the copper wire 12. The coating film 13 is made of an imide resin typified by polyimide, polyamideimide, polyesterimide or the like. The cross-sectional dimensions of the copper wire 12 are about 0.95 mm for the short side and about 2.40 mm for the long side, and the thickness of the coating film 13 is about 0.03 mm.

  The first coil 10a and the second coil 10b have opposite winding directions. Specifically, if one is right-handed, the other is left-handed. The size of the outer periphery of the first coil 10a is slightly smaller than the size of the inner periphery of the second coil 10b.

  FIG. 2 is a perspective view showing a state immediately before assembling the coils 10a and 10b. The coil wire end 11a of the flat wire 11 of the first coil 10a is bent, and the first coil 10a is inserted into the second coil 10b.

  FIG. 3 is a perspective view showing a state in which the first coil 10a is inserted into the second coil 10b. Both end portions of the first coil 10a and the second coil 10b are loosely fitted so that they are positioned on substantially the same plane.

  FIG. 4 is a perspective view showing a state in which the coil wire ends of the coils 10a and 10b are connected and the split stator is assembled. The coil wire ends 11a that terminate on the same side of the coils 10a and 10b are connected by a connecting member 10z. As a result, the first coil 10a and the second coil 10b are electrically connected in series via the connecting member 10z.

In the present embodiment, the connecting member 10z is located above the coil end portion. Thereby, the fall of a space factor can be suppressed.
The first coil 10a and the second coil 10b have the other coil wire end 11b as an external terminal. One coil wire end 11a is positioned on the tip end side (rotor side) of the tooth portion 51b, and the other coil tip end 11b is positioned on the yoke side. Although not shown, a bus bar connected to the other coil tip 11b is disposed on the yoke portion 51a.

  The split core 51 has a yoke part 51a and a teeth part 51b protruding from the yoke part 51a to the rotor side. In this embodiment, although the powder core structure is employ | adopted, you may use a laminated steel plate.

Although not shown in FIG. 4, the coil unit 10 includes a mold resin that molds the entire coil. The coil unit 10 is attached to the split core 51 by fitting the mold resin and the tooth portion 51 b of the split core 51. A split stator 53 is configured by the coil unit 10 and the split core 51.
At that time, the connecting member 10z and the coil wire end 10b which is an external terminal are exposed from the mold resin.

-Motor structure-
FIG. 5 is a cross-sectional view showing a schematic structure of stator 50 of the motor according to the first embodiment. Also in FIG. 5, the display of the mold resin is omitted. The stator 50 is configured by connecting a plurality of divided stators 53 in an annular shape. The stator 50 is assembled by enclosing a plurality of split cores 51 in an annular shape and enclosing from the outside using a ring member (not shown). In the present embodiment, a core in which the split cores 51 are assembled is used as the core, but the core may be integrated without being split.

A rotor (not shown) provided with permanent magnets is disposed inside the stator 50. In the present embodiment, the split core 51 is formed by compression molding magnetic powder having an insulating coating. However, a large number of silicon steel plates may be laminated with a resin insulating layer interposed therebetween.
A coil unit 10 including a first coil 10a and a second coil 10b is attached to the tooth portion 51b of the split core 51. Although the resin is not shown, the coil unit 10 is resin-molded.

FIG. 6 is a diagram showing an equivalent circuit of the stator 50 of the three-phase AC motor. The coil unit 10 of the split stator 51 is supplied with any of U-phase power, V-phase power, and W-phase power. In each phase, four coil units 10 are arranged in series, and the terminals of each coil unit 10 are electrically connected by a bus bar. The coil wire end 11b of the coil unit 10 located at the most central end of each phase is connected to the neutral point G via a bus bar. The coil wire end 11b of the outermost coil unit 10 connected in series is supplied with AC power converted from an inverter module or the like.
As shown in the enlarged view of FIG. 6, the first coil 10a and the second coil 10b are electrically connected in series via a connecting portion 10z.

-Effects of the embodiment-
According to the coil unit 10 or the stator 50 of the present embodiment, the following operational effects can be obtained.
In the coil unit 10, a plurality of coils 10a and 10b are connected in series without canceling the magnetic field. Therefore, no circulating current is generated. By connecting the coil wire ends 11a that terminate in the full face on the same side of the coils 10a and 10b, the connecting process is also simple. Also, the axial length can be suppressed.

Further, the other coil wire ends 10b serving as external terminals can be taken out from the same side. Therefore, if the other coil wire end 10b is on the rotor side, the bus bar can be disposed on the yoke portion 51a. Thereby, axial length can further be reduced.
Moreover, as compared with a coil in which one flat wire is wound in an edgewise manner, an adverse effect due to the skin effect can be suppressed.

(Embodiment 2)
FIG. 7 is a cross-sectional view of the divided stator in the second embodiment. In the figure, illustration of the mold resin is omitted. In FIG. 7, the same members as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
In the present embodiment, the first coil 10a and the second coil 10b are wound in a flatwise shape.
In FIG. 7, in order to facilitate understanding, the connecting member 10z that does not exist in this cross section is displayed.

In the first and second coils 10a and 10b, coil wire ends 11a that terminate in the end face on the same side are connected by a connecting member 10z.
Also in the present embodiment, the schematic structure of the stator 50 of the motor is as shown in FIG. An equivalent circuit of the stator 50 is as shown in FIG.

Also in the present embodiment, as in the first embodiment, the first and second coils 10a and 10b are electrically connected in series. In addition, coil wire ends 11a that are terminated on the same end face of each of the coils 10a and 10b are connected to each other.
Therefore, the same effect as Embodiment 1 can be exhibited. In addition, in this embodiment, the stress required for deformation at the time of winding can be reduced by winding in a flatwise shape. That is, the coil unit 10 can be easily formed.

(Other embodiments)
In each of the above embodiments, the coil unit 10 includes the two coils 10a and 10b. However, the present invention is not limited to this. Even when three or more coils are assembled from the inner side, the winding directions of adjacent coils may be reversed. Thereby, it is possible to connect the coil wire ends that terminate at the end surfaces on the same side.

  In each of the above-described embodiments, a structure in which the core 50 is divided into a large number of divided cores 51 is employed, but a plurality of divided cores 51 may be integrated.

  In each said embodiment, although the cross-sectional shape of the coil wire of each coil 10a-10c was made into the substantially rectangular shape, circular and other shapes may be sufficient.

  In each of the embodiments described above, a cassette coil structure molded with resin is employed as the coil unit 10, but the present invention is not limited to such an embodiment. However, by adopting a cassette coil structure, it is possible to use a modularized member for convenience of assembly and commercialization.

  The structure of the embodiment of the present invention disclosed above is merely an example, and the scope of the present invention is not limited to the scope of these descriptions. The scope of the present invention is indicated by the description of the scope of claims, and further includes meanings equivalent to the description of the scope of claims and all modifications within the scope.

  The coil unit and the stator of the present invention can be used for motors (including linear motors), generators, and the like disposed in industrial motors, hybrid vehicles, electric vehicles, fuel cell vehicles, robots, and the like.

It is a perspective view which shows the state which prepared each coil of the coil unit which concerns on Embodiment 1 of this invention. It is a perspective view which shows the state just before assembling each coil. It is a perspective view which shows the state which inserted the 1st coil in the 2nd coil. It is a perspective view which shows the state which connects the coil wire end of each coil and assembles a split stator. 2 is a cross-sectional view showing a schematic structure of a stator of the motor according to Embodiment 1. FIG. It is a figure which shows the equivalent circuit of the stator of a three-phase alternating current motor. FIG. 10 is a cross-sectional view of a divided stator in a second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Coil unit 10a 1st coil 10b 2nd coil 10z Connection part 11 Flat wire (coil wire)
11a, 11b Coil wire end 12 Copper wire 13 Coating film 50 Core 51 Divided core 51a Yoke part 51b Teeth part

Claims (4)

A coil unit in which a plurality of coils having different sizes in the radial direction are sequentially fitted from the inside,
Coil wires of two adjacent coils among the plurality of coils are wound in opposite directions,
A coil unit in which one end of each coil wire that terminates on the same end face of each coil is connected. The coil unit according to claim 1, wherein
Each said one coil wire end is a coil unit connected in the coil end part. A plurality of the coil units according to claim 1 or 2,
The same number of cores to which the plurality of coil units are respectively attached;
Stator with. The stator according to claim 3,
The other coil wire ends of the coil units are electrically connected at a yoke portion of the core.

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