JP2004208464A - Coil structure for electric motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coil structure of an electric motor, which can control the eddy current in a stator coil. <P>SOLUTION: By connecting electrically in parallel a plurality of wires 21 to 24 insulated to each other, conductor cross-section of parallel wires 2A positioned at least coil surface side is made smaller with wires wound that constitute a stator coil 2 in concentrated winding on the teeth 1A of a stator core 1B of the electric motor. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a winding structure of an electric motor, and more particularly, to a winding structure of an electric motor wound around a teeth portion of a stator.
[0002]
[Prior art]
Conventionally, permanent magnet embedded synchronous motors with a permanent magnet embedded inside the rotor core and a concentrated winding of the stator coil have been developed in order to respond to the demands of miniaturization, aiming for higher torque and higher output. It has been proposed (see Patent Document 1).
[0003]
[Patent Document 1]
JP 2000-69717 A
[Problems to be solved by the invention]
However, in a permanent magnet embedded synchronous motor having a concentratedly wound stator coil as in the conventional example described above, the number of teeth of the stator tends to be smaller than that of a general distributed winding, and the distance between the teeth is large. As a result, the leakage magnetic flux passing through the slot around which the coil is wound tends to increase. For this reason, the magnetic flux passing through the slot generates an eddy current, which is a loss inside the coil, which is the conductor wound around the slot. It is a factor that worsens.
[0005]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a winding structure of an electric motor capable of suppressing generation of an eddy current inside a stator coil.
[0006]
[Means for Solving the Problems]
The present invention relates to a plurality of conductors in which a conductor constituting a stator coil concentratedly wound around a tooth portion of a stator core of an electric motor has a conductor cross-sectional area of at least a conductor positioned on a coil surface side in a wound state, and insulated from each other. Are electrically connected in parallel, or made smaller by making the conductor inside the coil thinner.
[0007]
【The invention's effect】
Therefore, in the present invention, since the conductor cross-sectional area of at least the conductor positioned on the coil surface side in the wound state is formed to be small, eddy current (loss) generated in response to a temporal change of the leakage magnetic flux can be suppressed to a small value. The eddy current loss in the coil can be greatly suppressed, and the efficiency of the motor can be improved.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the winding structure of the electric motor of the present invention will be described based on each embodiment.
[0009]
(1st Embodiment)
1 to 3 show a first embodiment of a winding structure of a motor to which the present invention is applied. FIG. 1 is a partial sectional view of a stator of a first embodiment, and FIG. 2 is a part of a stator of a second embodiment. FIG. 3 is a sectional view of the stator according to the third embodiment.
[0010]
In FIG. 1 showing a first embodiment of a winding structure of an electric motor, a stator 1 has a cylindrical stator core 1B provided with a teeth portion 1A having a convex shape toward the inner peripheral side (rotor side) of the motor, and teeth of the stator core 1B. The stator coil 2 is wound around the portion 1A by concentrated winding, and 3N (N is an integer of 1 or more) teeth portions 1A in which the stator coil 2 is concentratedly wound are arranged and provided in the circumferential direction.
[0011]
The stator core 1B is provided with a plurality of teeth portions 1A protruding inward from a cylindrical yoke portion 1C and arranged in the circumferential direction, and usually has a magnetic shape including a yoke portion 1C and a plurality of teeth portions 1A. A plurality of steel plates are integrated in a state of being stacked in the axial direction.
[0012]
The stator coil 2 (hereinafter, referred to as a coil) is formed of a conductor made of a conductor made of a highly conductive material such as copper and coated with an insulating material such as enamel. A state in which a plurality of conductive wires 21 to 24 having a conductor cross-sectional area smaller than that of a general conductive wire are bundled, for example, every four wires, from the beginning to the end of the coil 2 wound around the teeth portion 1A by concentrated winding. The parallel conductors 2A (21 to 24) in a bundled state are electrically connected to each other at a portion drawn out from a winding start end and a winding end end (not shown). The parallel conductive wires 2A (21 to 24) from the beginning to the end of the winding are electrically connected in parallel. Even between the bundled parallel conductors 2A (21 to 24), a coating is applied with an insulating material such as enamel so as to prevent direct electrical conduction due to contact with each other to insulate the conductors. FIG. 1 shows a sectional view of the parallel conductors 2A (21 to 24) of the coil 2 wound around the teeth portion 1A of the stator core 1B in a state of being bundled every four.
[0013]
When a predetermined current is applied to the coil 2 of the stator, a magnetic action is generated between the teeth portion 1A and a rotor (not shown) provided on the inner peripheral side of the stator 1 via an air gap, and a rotor having a permanent magnet embedded therein is generated. To rotate. At this time, between the adjacent teeth portions 1A of the stator 1, a leakage magnetic flux which does not participate in the magnetic action with the rotor may be generated. It is known that this leakage magnetic flux is greatest at the inner peripheral side (rotor side) portion of the coil 2, and the leakage magnetic flux changes with time due to a change in the current of the coil 2 or rotation of the rotor. That is, the leakage magnetic flux increases as the exciting current increases, and the temporal change increases as the frequency of the exciting current increases. When the leakage flux changes over time, an eddy current is generated in the conductors 21 to 24 forming the coil 2.
[0014]
However, in the winding structure of the electric motor of the present embodiment, a plurality of, for example, 4 parallel conductive wires 2A are wound around the teeth portion 1A of the stator 1 of the stator coil 2 by concentrated winding from the beginning to the end of winding. Since the conductors 21 to 24 each having a smaller conductor cross-sectional area than a general conductor in a state of being bundled for each book, an increase in resistance to an exciting current can be suppressed to be small. In addition, since the parallel conductors 2A (21 to 24) have small conductor cross-sectional areas, eddy currents (losses) generated in response to the temporal change of the leakage magnetic flux can be reduced. Therefore, the eddy current loss in the coil can be greatly suppressed without increasing the copper loss caused by the resistance to the exciting current, and the efficiency of the motor can be improved.
[0015]
In the present embodiment, a case has been described in which, as the parallel conductors 2A (21 to 24), conductors 21 to 24 each having a smaller conductor cross-sectional area than a general conductor are bundled every four wires. May be bundled. Although the case where the parallel conductors 2A (21 to 24) are wound in a bundled state has been described, the conductors 21 to 24 of the parallel conductors 2A (21 to 24) are not bundled, but not bundled. May be repeated a predetermined number of times, for example, four times for the number of the parallel conductors 2A (21 to 24), and thereafter, the ends of the conductors 21 to 24 may be connected to each other to be in parallel. Well, similar effects can be obtained. In addition, a circular cross section has been described as the cross-sectional shape of the conductors 21 to 24 constituting the parallel conductors 2A (21 to 24), but a quadrilateral cross-section may be used, although not shown, and other cross-sections may be used. The conductor may have any cross-sectional shape.
[0016]
FIG. 2 is a partial cross-sectional view of a stator illustrating a winding structure of a motor according to a second example of the first embodiment. In this embodiment, the parallel conducting wires are mechanically connected in advance to facilitate the winding. The same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted or simplified.
[0017]
In FIG. 2, a coil 2 wound around a tooth portion 1A of a stator 1 has a plurality of conductors 21 to 24 of a parallel conductor 2A obtained by bundling a plurality of conductors having a small conductor cross-sectional area. It is formed by mechanical coupling. In addition, in the figure, as the cross sections of the conductors 21 to 24 configuring the parallel conductor 2A, a conductor having a quadrangular cross section is shown, but a circular conductor may be used, or another cross section may be used. The conductor may have any cross-sectional shape.
[0018]
According to this configuration, in order to partially wind the plurality of conductors 21 to 24 in parallel connection, the conductors 21 to 24 can be wound around the teeth portion 1 </ b> A as if they are one conductor, and can be concentratedly wound. . Therefore, there is an advantage that the conventional winding equipment can be used without changing the equipment and the time required for the winding is the same as the conventional one. When such a configuration is not used, the conductors 21 to 24 of the parallel conductor 2 </ b> A are bundled or the like, and a plurality of conductors 21 to 24 are aligned and wound at once, or each of the plurality of conductors 21 to 24 is wound. It is necessary to repeat the operation of winding a predetermined number of turns a plurality of times to electrically connect the ends.
[0019]
FIG. 3 is a partial cross-sectional view of a stator illustrating a winding structure of a motor according to a third example of the first embodiment. The present embodiment provides a conductor shape of a parallel conductor that can effectively suppress eddy currents.
[0020]
In FIG. 3, the coil 2 wound around the teeth portion 1A of the stator 1 has a parallel conductor 2A (21 to 24) having a rectangular or rectangular shape having a short side in the motor radial direction and a long side in the circumferential direction. It has an elliptical shape.
[0021]
The leakage magnetic flux passing through the coil 2 from the side surface of the tooth portion 1A is directed to the adjacent tooth 1A or the rotor. When considering this leakage magnetic flux separately in the circumferential and radial components of the motor, the circumferential component is usually larger than the radial component in the coil 2 portion, and the eddy current is perpendicular to the direction of the magnetic flux. Occurs in the direction. For this reason, the eddy current generated in the conductor can be effectively suppressed by making the conductor shape of the coil 2 a shape having a short side in a direction perpendicular to the direction of the magnetic flux as in the present embodiment.
[0022]
Desirably, the conductors 21 to 24 of the parallel conductor 2A are formed by mechanically connecting a plurality of thin conductors 21 to 24 having a small conductor cross-sectional area to each other in advance by bonding with an adhesive or the like. That is, when the thin conductive wires 21 to 24 are collectively wound around the teeth 1A, the long sides of each of the conductive wires 21 to 24 fall down along the radial direction of the motor, and the teeth 21A around the tooth portion 1A. Although it is very difficult to align the wires, a plurality of these wires 21 to 24 are mechanically coupled together so that they can be handled as if they were a single wire. There is an advantage that it can be used without changing the equipment and the like for the winding, and the time required for the winding is not different from the conventional one.
[0023]
In the present embodiment, the following effects can be obtained.
[0024]
(A) Conductor cross-sections of conductors 21 to 24 which are positioned at least on the surface side of coil 2 in a state where conductors 21 to 24 constituting stator coil 2 wound around teeth portion 1A of stator core 1 of the electric motor are wound. Is made by electrically connecting a plurality of insulated wires 21 to 24 electrically in parallel to each other, so that the eddy current (loss) generated in response to the temporal change of the leakage magnetic flux can be suppressed to a small value. The eddy current loss in the inside can be greatly suppressed, and the efficiency of the motor can be improved.
[0025]
(A) Conductors 21 to 24 constituting one coil 2 are formed by a plurality of conductors 21 to 24 which are insulated from each other between the start and end of winding of the teeth portion 1A, and the winding start portion and the end of winding are formed. Since the plurality of conductive wires 21 to 24 are electrically connected to each other at a portion, an eddy current loss generated in response to a temporal change of a leakage magnetic flux can be suppressed small, and an eddy current loss in the coil 2 is greatly reduced. Can be suppressed. In addition, an increase in resistance to the exciting current can be suppressed small, an increase in copper loss caused by the resistance to the exciting current can be suppressed, and the efficiency of the motor can be improved.
[0026]
(C) In the embodiment shown in FIG. 2 and FIG. 3, since the plurality of conductive wires 21 to 24 insulated from each other are mechanically joined, the teeth portion 1A is connected to the tooth portion 1A as if it were a single conductive wire. Winding can be performed in a concentrated manner, so that it can be used without changing equipment and the like for windings that have been conventionally used, and the time required for winding has the same effect as in the past.
[0027]
(D) In the embodiment shown in FIG. 3, the shape of each of the plurality of conductive wires 21 to 24 insulated from each other is formed into a substantially rectangular or elliptical cross section having a short side in the radial direction of the motor and a long side in the circumferential direction. As a result, the shape can be such that there is a short side in the direction perpendicular to the direction of the magnetic flux, and the eddy current generated in the conductor can be more effectively suppressed.
[0028]
(2nd Embodiment)
4 to 6 show a second embodiment of a winding structure of a motor to which the present invention is applied. FIG. 4 is a partial cross-sectional view of the stator of the first embodiment, and FIG. 5 is a part of the stator of the second embodiment. FIG. 6 is a sectional view of the stator according to the third embodiment. In the present embodiment, only the conductor portion of the coil where eddy current loss occurs is formed by a conductor having a small conductor cross-sectional area. The same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted or simplified.
[0029]
In FIG. 4, a coil 2 wound around a tooth portion 1 </ b> A of a stator 1 is a parallel conductor obtained by binding a plurality of conductors 21 to 24 having a small conductor cross-sectional area to a conductor located at a surface side in a wound state. The conductive wire 2B formed of 2A and located inside in a wound state is formed of one conductive wire 2B having a large conductor cross-sectional area.
[0030]
As described above, the leakage magnetic flux which does not participate in the magnetic action with the rotor is largest at the inner circumference side (rotor side) of the coil 2, and thus the eddy current loss generated inside the conductor of the coil 2 is particularly large in the inner circumference. Tends to concentrate on the coil 2 on the side (rotor side). Therefore, by using a parallel conductor 2A composed of a plurality of conductors 21 to 24 having a small conductor cross-section with respect to a conductor located at a portion where the eddy current is concentrated, each conductor cross-section is reduced, and the leakage magnetic flux is reduced. Eddy current (loss) generated in response to a temporal change is suppressed to a small value. Therefore, the eddy current loss in the coil 2 can be largely suppressed, and the efficiency of the motor can be improved.
[0031]
In addition, the use of the parallel conductor 2A with the conductors 21 to 24 having a small conductor cross-section is used only for the conductor 2A located at a portion where the eddy current is concentrated from the beginning to the end of the winding, and the remaining conductor is used. Since a single conductor having a large conductor cross-sectional area is used for 2B, the resistance to the exciting current in this portion can be reduced, and the increase in copper loss can be minimized. That is, in the case where the total conductor cross-sectional area is the same between one generally used conductor 2B and the parallel conductor 2A in which the conductors 21 to 24 having a smaller conductor cross-sectional area than the general conductor are bundled. In addition, the ratio of the conductor occupying the same area of the latter, that is, the space factor, tends to be inevitably reduced due to the amount of the insulating film and the gap at the time of bundling. Therefore, the copper loss caused by the exciting current slightly increases in the parallel conducting wire 2A. However, in the vicinity of the root of the tooth 1A or near the center of the coil 2 where there is almost no influence of the eddy current due to the leakage magnetic flux, an increase in the copper loss can be suppressed to a minimum because the general single conductor 2B is used. is there.
[0032]
In addition, although the cross-sectional shape of the conductor which comprises one conductor 2B and the parallel conductor 2A was demonstrated to be circular, although not shown, a quadrangular cross-section may be sufficient and other cross-sections may be sufficient. The cross section of the conductive wire may be any shape.
[0033]
FIG. 5 is a partial cross-sectional view of a stator showing a winding structure of a motor according to a second example of the second embodiment. In the present embodiment, the coil 2 wound around the teeth portion 1A of the stator 1 forms the conductor 25 at a portion located on the front surface side in a wound state by a single conductor having a small conductor cross-sectional area, The conductive wire 26 located inside in the wound state is formed by a single conductive wire having a large conductor cross-sectional area, and two types of conductive wires 25 and 26 are connected in parallel. In the drawing, as the cross section of each of the conductors 25 and 26, a conductor having a quadrangular cross section is shown. However, the conductor may have a circular shape or another cross section. Anything may be used.
[0034]
Also in this embodiment, since the eddy current is largely concentrated on the outer periphery of the coil 2, particularly on the rotor side, a conductor 26 having a relatively large conductor area is used in other portions, and the conductor area is provided on the outer side of the coil, especially on the rotor side. Eddy current loss of the coil 2 can be effectively suppressed without increasing the copper loss due to the exciting current by using the conductive wires 25 having a small diameter.
[0035]
FIG. 6 is a partial cross-sectional view of a stator illustrating a winding structure of a motor according to a third example of the second embodiment. In the present embodiment, the coil 2 wound around the teeth portion 1A of the stator 1 forms a conductor at a portion located on the surface side in a wound state with one conductor 27 having a small conductor cross-sectional area, A conductive wire located inside in a wound state is formed by one conductive wire having a large conductor cross-sectional area, and two types of conductive wires 27 are connected in series. In the two types of conductors, first, the conductor 28 having the larger conductor cross-sectional area is wound N1 times around the teeth portion 1A, and then the conductor 27 having the smaller conductor area is wound N2 times. The thin conductive wire 27 wound later is wound so as to concentrate on the rotor side of the coil 2. By setting the total number of turns (N1 + N2) to the initial predetermined number of turns, the effect of suppressing the eddy current can be obtained as in the previous embodiments. In addition, in the figure, as the cross section of each of the conductors 27 and 28, a conductor having a circular cross section is shown, but a conductor having a quadrangular cross section or another cross section may be used. Anything may be used.
[0036]
In the present embodiment, the following effects can be obtained.
[0037]
(E) Conductor cross-sectional areas of the conductors 21 to 24, 25, and 27 that are at least located on the coil surface side in a wound state, in which the conductor forming the stator coil 2 wound around the teeth portion 1A of the stator core 1B of the electric motor is wound. Is made smaller by making the conductors 2B, 26, and 28 inside the coil thinner, the eddy current (loss) generated in response to the temporal change of the leakage magnetic flux can be reduced, and the eddy current loss in the coil 2 can be reduced. And the efficiency of the motor can be improved.
[0038]
(F) In the embodiment shown in FIG. 4, a plurality of conductive wires 21 to 24 which are insulated from each other at least by a coil portion located on the surface side in a wound state are formed by electrically connecting a conductive wire constituting one coil 2. Since the configuration is connected in parallel, the increase in resistance to the exciting current can be suppressed to a small value. Further, since the parallel conductor 2A has a small cross-sectional area of each conductor, the eddy current generated in response to the temporal change of the leakage magnetic flux is generated. (Loss) can be suppressed small. Therefore, the eddy current loss in the coil 2 can be greatly suppressed without increasing the copper loss caused by the resistance to the exciting current, and the efficiency of the motor can be improved.
[0039]
(G) In the embodiment shown in FIG. 5, if the conductor forming one coil 2 has a different conductor cross-sectional area than the coil surface-side conductor 25 located on the surface side in the wound state, and the surface-side conductor 25, The coil inner conductive wire 26 wound inside the coil is electrically connected at a winding start portion and a winding end portion. That is, since the eddy current is largely concentrated particularly on the rotor side of the outer periphery of the coil 2, a conductor 26 having a relatively large conductor area is used in other portions, and a conductor 25 having a small conductor area is provided outside the coil, particularly on the rotor side. These are connected in parallel, so that the exciting current mainly flows through the coil inner conductor 26 having a large conductor cross-sectional area, so that the copper loss does not increase, and the remaining amount of the exciting current flows through the coil surface. The side conductor 25 has a small conductor cross-sectional area, and can greatly suppress the eddy current loss of the coil 2.
[0040]
(H) In the embodiment shown in FIG. 6, the conductor forming one coil 2 is wound in the wound state on the coil inner conductor 28 in series with the coil inner conductor 28 and wound on the coil surface side. And the coil inner conductor 28 and the coil surface conductor 27 have different cross-sectional areas. That is, first, the conductor 28 having a larger conductor cross-sectional area is wound N1 times around the teeth portion 1A, and then the conductor 27 having a smaller conductor area is wound N2 times, and the thinner conductor 27 wound later is formed by a coil. Since the windings are concentrated so as to concentrate on the rotor side of No. 2, by setting the total number of turns (N1 + N2) to the initial predetermined number of turns, the effect of suppressing the eddy current can be obtained as in the previous embodiments. .
[Brief description of the drawings]
FIG.
1 is a partial cross-sectional view of a stator according to a first example of a winding structure of an electric motor according to an embodiment of the present invention.
FIG. 2 is a partial cross-sectional view of a stator of a second example of the winding structure of the electric motor according to the first embodiment of the present invention.
FIG. 3 is a partial cross-sectional view of a stator of a third example of the winding structure of the electric motor according to the first embodiment of the present invention.
FIG. 4 is a partial cross-sectional view of a stator of a first example of a winding structure of an electric motor according to a second embodiment of the present invention.
FIG. 5 is a partial sectional view of a stator according to a second example of the winding structure of the electric motor according to the second embodiment of the present invention.
FIG. 6 is a partial sectional view of a stator according to a third embodiment of the winding structure of the electric motor according to the second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Stator 1A Teeth part 1B Stator core 1C Yoke part 2 Coil, stator coil 2A Parallel conducting wires 21-24, 2B, 25-28 conducting wires

Claims (7)

In a winding structure of an electric motor having a stator coil concentratedly wound around a tooth portion of a stator core,
A winding of an electric motor, wherein a plurality of conducting wires which are insulated from each other at least in a coil portion located on a surface side in a wound state are formed by electrically connecting a plurality of conducting wires constituting one coil. Line structure. The conductor forming the one coil is formed by a plurality of conductors insulated from each other between the start and end of winding on the teeth portion, and the plurality of conductors are electrically connected to each other at the winding start portion and the winding end portion. The winding structure for an electric motor according to claim 1, wherein the winding structure is connected to the motor. 3. The winding structure for an electric motor according to claim 1, wherein the plurality of conductive wires insulated from each other are mechanically joined. The plurality of conductive wires insulated from each other have a substantially rectangular or elliptical cross-section in which each conductive wire shape has a short side in a radial direction of the motor and a long side in a circumferential direction of the motor. 3. The winding structure of the electric motor according to any one of 3. In a winding structure of an electric motor having a stator coil concentratedly wound around a tooth portion of a stator core,
A winding structure for an electric motor, wherein a conductor constituting one coil is formed such that a conductor cross-sectional area of at least a conductor located on the coil surface side in a wound state is smaller than a conductor inside the coil. A conductor constituting the one coil, a coil surface-side conductor positioned on the surface side in a wound state, and a coil-side conductor wound inside the coil with a different conductor cross-sectional area from the surface-side conductor. 6. The winding structure for an electric motor according to claim 5, wherein the first and second windings are electrically connected at a winding start portion and a winding end portion. The conductor forming the one coil includes a coil inner conductor in a wound state, and a coil surface-side conductor connected in series to the coil inner conductor and wound on the coil surface side, and a coil inner conductor. 6. The winding structure for an electric motor according to claim 5, wherein a cross-sectional area of the coil and a coil surface side conductive wire are different.

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