JP2011147312A - Stator and motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stator for a motor which can increase a space factor of a coil, can suppress an eddy loss which may be generated at a conductor facing a slot opening, and is improved in torque performance, and to provide the motor equipped with the stator. <P>SOLUTION: In a stator core 10 composed of a yoke 12 which is formed into a substantially annular or arc shape in a plane view, and teeth 11 which protrude radially inward from the yoke 12, the stator 100 is formed with the coil which is formed by winding the conductor 20 around the external periphery of each of the teeth 11, the coil is composed of a single conductor in which two or more kinds of divided conductors different in dimensions of cross sections are connected to each other, the divided conductors (round cross-section conductors 22) which are relatively small in the dimensions of the cross sections are arranged at radial tip sides of the teeth 11, and the divided conductors (rectangular wires 21) which are relatively large in the dimensions of the cross sections are arranged at the yoke side. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a stator in which a coil is formed by winding a conductive wire around the teeth of a stator core, and a motor including the stator.

  A stator constituting a motor (electric motor) is a stator core formed by laminating steel plates each having an annular yoke, a plurality of teeth projecting radially inward from the yoke, and slots formed between adjacent teeth. The stator having the coil is manufactured by being wound between the teeth while the conductive wire is inserted into the slot.

  Here, the lead wire for the coil is generally circular in cross section, and is composed of, for example, a copper lead wire and an insulating film formed around the lead wire. And either one of the concentrated winding method and the distributed winding method is applied as the winding form, and in the case of the concentrated winding method, a conductive wire is wound for each tooth, and a coil is wound around one tooth. In the case of the distributed winding method, a heterogeneous coil having, for example, a U phase, a V phase, and a W phase is formed across a plurality of teeth. In any winding method, slot insulating paper is interposed between them from the viewpoint of ensuring insulation between the slot wall surface and the coil. In the case of the distributed winding method, a different-phase coil at the coil end is further provided. Interphase insulating paper is interposed for insulation between the conductors, and insulation between the conductors, slot insulation, and interphase insulation are achieved by an insulating film and insulating paper constituting the conductors.

  By the way, for the purpose of increasing the space factor of the coil, for example, a rectangular wire having a substantially rectangular cross-sectional view is used in place of the circular cross-sectional wire constituting the rotor disclosed in Patent Document 1. A coil formed by arranging the coils around the teeth is also known, and Patent Document 2 discloses a stator including a coil made of a rectangular wire (rectangular wire).

  On the other hand, when the motor is driven, there is a problem of eddy loss that occurs in the conducting wire forming the coil. This will be described with reference to FIG. 5 showing a coil of concentrated winding form. The motor of the illustrated example has a stator S in which teeth T protrude radially from a yoke Y, and the above-described rectangular wire W is formed between slots SL defined between adjacent teeth T and T and around the teeth T. It is wound and a coil is formed.

  Here, when the rotor R rotates at the time of driving the motor (Z direction), a part of the magnetic flux that should originally flow from the teeth T to the permanent magnet E in the rotor R is caused by the magnetic field fluctuation generated between the rotor R and the stator S. The leakage magnetic flux M1 flows so as to wrap around the rectangular wire W facing the slot opening SK. In addition, a part of the magnetic flux flowing from the permanent magnet E to the tooth T does not flow into the tooth T, but a part thereof flows as a leakage magnetic flux M2 to the rectangular wire W facing the slot opening SL.

  In this way, a part of the magnetic flux that should flow directly into the permanent magnets of the teeth and the rotor can often flow into the conducting wire located in the slot opening as a leakage magnetic flux. It is known that it cannot contribute to the motor torque and causes eddy loss (copper conductors are generally used, but copper loss due to Joule heat generated when current flows through the conductor itself) To distinguish, it is sometimes called copper vortex loss).

  In order to improve the space factor, when the above-described rectangular wire is used, the area of the conductive wire facing the slot opening (facing the rotor), that is, the area where the leakage magnetic flux intersects is large. In particular, the eddy loss is likely to be larger than that of a small-diameter cross-section conductor, and there is a concern that the motor torque performance may be reduced due to this.

  From the various problems described above, both the improvement of the space factor of the wire wound around the teeth and the reduction of copper loss caused by the leakage magnetic flux from the tip of the teeth and the rotor were satisfied, and the torque performance was excellent. The development of motors is an urgent issue that is eagerly desired in the field.

Japanese Patent Laid-Open No. 5-111202 JP 2002-223542 A

  The present invention has been made in view of the above-described problems, and can increase the space factor of the coil, and can suppress vortex loss that can occur in the conductive wire facing the slot opening, and thus has excellent torque performance. Another object is to provide a stator for a motor and a motor including the stator.

  In order to achieve the above object, a stator according to the present invention includes a substantially annular or arcuate yoke in plan view and a tooth projecting radially inward from the yoke. The coil is formed of a stator, and the coil is composed of a single conductor in which two or more types of segmented conductors having different cross-sectional dimensions are connected to each other, and has a relatively small sectional dimension. The conducting wire is disposed on the radial front end side of the teeth.

  The stator of the present invention includes a stator in which a plurality of teeth protrudes radially inward from a substantially annular yoke in plan view, and a split core in which one tooth protrudes radially inward from an arcuate yoke in plan view. For example, both of the divided stators that are assembled in the circumferential direction, for example, are formed by fitting a cylindrical body to the outer periphery of the assembled body and performing shrink fitting or the like.

  Further, this stator core is formed of a steel sheet laminate formed by laminating electromagnetic steel sheets and the like, as well as iron, iron-silicon alloy, iron-nitrogen alloy, iron-nickel alloy, iron-carbon alloy. , Iron-boron alloys, iron-cobalt alloys, iron-phosphorus alloys, iron-nickel-cobalt alloys and iron-aluminum-silicon alloys, or soft magnetic metal oxide powders are silicones. The object is also formed from a powder magnetic core made of magnetic powder coated with a resin binder such as resin, a high-density powder magnetic core (HDMC), or the like.

  A single wire in which two or more kinds of divided conductors having different cross-sectional dimensions (cross-sectional dimensions) are connected is wound around the outer periphery of the teeth to form a coil. The conductor of this invention is formed by arrange | positioning conducting wire to the radial direction front end side of teeth. Here, as the cross-sectional shape of the divided conducting wire, an appropriate cross-sectional shape can be selected from circular, elliptical, rectangular, square and the like. In addition, the ratio of the cross-sectional dimensions of both of the divided conducting wires to be connected can be selected as a small cross-sectional dimension / large cross-sectional dimension having an arbitrary ratio such as 0.5, 0, 3, 0.2.

  For example, a conductive wire in which two types of conductive wires having different cross-sectional dimensions are connected is used, a conductive wire having a relatively large cross section is disposed on the yoke side of the teeth, and a relatively small cross section is provided on the tooth tip side (rotor side). A coil configuration in which three conductors with different cross-sectional dimensions are connected, or a coil configuration in which the cross-sectional dimension gradually decreases from the tooth yoke side to the tip end side. There are various forms.

  Regarding the joining of segmented conductors with different cross-sectional dimensions, for example, when both segmented conductors are composed of a copper-based conductor body and an enamel insulating film formed therearound, part of the insulating film on both end regions The exposed portion of the internal conductor is formed by removing the wire, the exposed portions of the two divided conductors are brought into contact with each other, and the conductor for the continuous coil whose cross-sectional dimension changes from the middle is formed by thermocompression bonding or the like. be able to.

  According to the stator of the present invention, a relatively large cross-section conducting wire is arranged on the yoke side of the teeth, thereby increasing the space factor, and a relatively small cross-sectional conducting wire is arranged on the tooth tip side. Therefore, the passage area of the leakage magnetic flux described above can be reduced as much as possible, and the copper loss (copper vortex loss) that can be generated can be suppressed. It is a stator that constitutes an excellent motor.

  As a combination of the above-described divided conducting wires, for example, the divided conducting wire wound around the yoke side of the teeth can be a flat wire, and the divided conducting wire on the distal end side in the radial direction of the teeth can be a conducting wire having a circular cross section.

  This configuration can increase the space factor of the entire coil by using a flat wire for the divided conductor arranged on the yoke side of the tooth. Compared to the case where a rectangular wire is applied to this part, the area where the leakage flux intersects can be made much smaller and the copper loss is minimized. It can be suppressed to the limit. In addition, both of the divided conductors are conventional ordinary conductors. For example, since only processing for connecting the end regions of the two kinds of conductors is added, there is no possibility that the manufacturing cost will increase.

  Further, in a preferred embodiment of the stator according to the present invention, both ends are abutted via a conductive member, a crimp terminal is disposed around the end and the conductive member, and the crimp terminal is crushed. The split conducting wires are connected to each other in a different posture.

  This form can suppress the height increase of the said coil end as much as possible, when this junction part is arranged by a coil end, for example by abutting the edge parts of a split conducting wire through a conductive member It is a stator.

  For example, a conductive member made of the same material as that of the conducting wire is arranged between the ends of the divided conducting wires, so that the continuous conducting wires can be connected while eliminating the abutting failure that may occur when both ends are directly matched. Can be formed. Further, by enclosing the butted region with the crimp terminal on the outer periphery and further crushing the crimp terminal, it is possible to secure the connection posture and secure its strength. In addition, this conductive member has a cross-sectional dimension comparable to that of a conductive wire having a relatively large cross-sectional dimension, and is preferably formed from the same material as that of the conductive wire (when the conductive wire is a copper material, the conductive material of the copper material is used). Sex member).

  Moreover, as a more preferable embodiment, it is preferable that an end portion of the divided conducting wire that is abutted with the conductive member has an uneven surface.

  According to this aspect, the end portions of both divided conductors to be connected can be reliably engaged with the conductive member, and the connection (contact) between the divided conductor end portions and the conductive member can be more reliably ensured. it can.

  Further, according to the present inventors, in the motor including the stator of the present invention, the copper vortex loss can be reduced by about 5% as compared with the motor including the stator having the conventional structure. In the form in which the end portions of each other are abutted through the conductive member, it has been demonstrated that the increase in the height of the coil end can be suppressed to about 10%.

  By producing a motor (electric motor) equipped with the stator of the present invention, the coil space factor can be increased as much as possible, and copper vortex loss caused by magnetic flux leakage from the teeth and rotor can be suppressed as much as possible. Thus, a motor having excellent torque performance can be obtained. Therefore, the motor having the stator of the present invention is suitable for a drive motor of a hybrid vehicle or an electric vehicle, which has recently been mass-produced and is expected to have high output performance.

  As can be understood from the above description, according to the stator of the present invention, a single conductive wire in which two or more types of divided conductive wires having different cross-sectional dimensions are connected is wound around the outer periphery of the tooth to form a coil, By forming a split conducting wire having a relatively small cross-sectional dimension on the distal end side in the radial direction of the teeth, the space factor of the coil can be increased by the split conducting wire having a relatively large cross-sectional dimension, The crossing area of the leakage magnetic flux can be made as small as possible by the split conducting wire having a relatively small cross-sectional dimension, and a motor excellent in torque performance can be configured by both actions.

It is the cross-sectional view which took out some stators of this invention. (A) is sectional drawing of one Embodiment of the connection structure of a division | segmentation conducting wire, (b) is a bb arrow line view of FIG. 2a. (A) is a top view of other embodiment of the connection structure of a division | segmentation conducting wire, (b) is a bb arrow line view of FIG. 3a. It is a top view of other embodiment of the connection structure of a division | segmentation conducting wire. It is the schematic diagram explaining the condition where the leakage magnetic flux from a tooth | gear and the leakage magnetic flux from a rotor are flowing in the coil which comprises the conventional stator.

  Embodiments of the present invention will be described below with reference to the drawings. In the illustrated example, a single conductor is formed from two types of divided conductors having different cross-sectional dimensions. However, a single conductor formed by mutually connecting three or more types of divided conductors having different cross-sectional dimensions is used. Of course, a conducting wire may be applied. In addition, the illustrated example is a stator in which conductive wires are concentratedly wound, but it goes without saying that a stator in which conductive wires are distributedly wound may be used. Furthermore, it goes without saying that a divided stator in which the divided stator core is assembled in the circumferential direction may be used in addition to the illustrated stator. In addition, illustration of the slot insulation paper intervening on the side surface of the teeth or the slot surface, the bobbin wound around the coil and fitted into the teeth is omitted.

  FIG. 1 is a cross-sectional view of a part of the stator according to the present invention. First, the stator core 10 includes a steel plate laminate formed by laminating steel plates such as electromagnetic steel plates, cold rolled steel plates (SPCC), hot rolled steel plates (SPHC), carbon steel (S45C), soft magnetic metal powders or soft The magnetic metal oxide powder is formed from a powder magnetic core formed by press-molding magnetic powder coated with a resin binder such as silicone resin or silica.

  The stator core 10 includes a substantially annular yoke 12 and a plurality of teeth 11,... Projecting radially inward from the yoke 12, and a plurality of permanent magnets are disposed inside the teeth 11,. A motor (IPM motor or the like) is configured by arranging a rotor (not shown) formed by embedding a wire.

  A coil wire 20 is wound around each tooth 11 by connecting a flat wire 21 (a flat wire) and a circular cross-section wire 22 having a cross-sectional dimension much smaller than that of the flat wire 21. A coil is formed and the stator 100 is configured.

  The coil wire 20 will be described in more detail with respect to this winding form. The coil wire 20 is provided with a plurality of rectangular wires 21 having a relatively large cross-sectional dimension on the yoke 12 side of the teeth 11, and then the teeth 11 from the middle of the teeth 11. The circular cross-section conducting wires 22 having relatively small cross-sectional dimensions are arranged in multiple stages toward the front end of these, and these close the inside of the slot 13 defined between the adjacent teeth 11 and 11.

  In this way, the rectangular wire 21 closes the area of the slot 13 on the yoke side, so that the coil space factor can be increased as much as possible.

  As is clear from FIG. 1, since the lead wire facing the slot opening 13 is a circular cross-section lead wire 22 having a relatively small cross-sectional dimension, leakage flux from the rotor side (not shown) and the tip of the teeth 11 are not shown. When the leakage magnetic flux enters the slot opening portion 13a, the conductor area intersecting with the slot opening portion 13a can be made as small as possible. This leads to a reduction in copper vortex loss that can occur in the conductor due to leakage magnetic flux. For example, the amount of eddy loss is much smaller than when a flat wire is facing the slot opening. Can be suppressed.

  In the illustrated example, the circular cross-section conductor 22 is wound in multiple stages (three stages in the figure), but it may be configured to have only one round cross-section conductor 22 facing the slot opening 13a. In this embodiment, only the area of the conducting wire facing the slot opening 13a can be reduced while maximizing the coil space factor.

  2 to 4 illustrate a connection structure between two conductive wires having different cross-sectional dimensions that constitute the coil conductive wire 20.

  First, regarding FIG. 2, FIG. 2a is sectional drawing of one Embodiment of the connection structure of a division | segmentation conducting wire, FIG. 2b is a bb arrow line view of FIG. 2a.

  This connection structure 30 is a structure in which one rectangular wire 21 and three circular cross-section conductors 22, 22, 22 are connected at both end regions. More specifically, in the flat wire 21 composed of the copper wire 21a and the enamel coating 21b around the copper wire 21a, a part of the enamel coating 21b in the end region is removed to form an exposed portion 21a ′ of the copper wire 21a. In addition, in the circular cross-section conducting wire 22 composed of the copper wire 22a and the enamel coating 22b around the copper wire 22a, an exposed portion 22a ′ of the copper wire 22a is formed by removing a part of the enamel coating 22b in the end region. They are in contact with each other and thermocompression bonded.

  In the actual coil formation, the connection structure 30 is preferably adjusted so as to come to the coil end. By adopting such a coil posture, the connection structure 30 is arranged in the slot. The reduction of the space factor at the time can be suppressed.

  On the other hand, FIG. 3 shows a separate connection structure, FIG. 3a is a plan view of the connection structure of the divided conductors, and FIG. 3b is a view taken along the line bb of FIG. 3a.

  Also in this connection structure 30A, one rectangular wire 21 and three circular cross-section conductors 22, 22, 22 are connected. This is, for example, a copper material sandwiching a fixed conductive member 40. The flat wire 21 and the circular cross-section conductor 22 are indirectly connected, and a tubular crimp terminal 50 is arranged around the ends of both the conductive member 40 and the flat wire 21 and the circular cross-section conductor 22, and this is crushed and connected. A structure 30A is formed.

  In addition, although the thing of various forms can be used for the crimp terminal 50, generally, a connection location is pinched | interposed with an upper and lower insulating terminal, and this is crushed and forms a tubular attitude | position, thereby dividing | segmenting conducting wires When the connection structure 30A is formed at the coil end, the increase in the coil end height is effective. Can be suppressed.

  FIG. 4 shows a further connection structure. In this connection structure 30B, the end surface of the flat wire 21 is an uneven surface 21 ′, and the end surface of the circular cross-section conductor 22 is also an uneven surface 22 ′, and the uneven surface 21 ′, 22 ′ sandwiches the conductive member 40 and is crimped. Terminals 50 are formed around them.

  According to this connection structure 30B, the ends (uneven surfaces 21 ′ and 22 ′) of both divided conductors to be connected are securely meshed with the conductive member 40, and both ends of the divided conductors 21 and 22 are connected to the conductive member. The connection with the sex member 40 can be more reliably ensured.

[Analysis and results comparing the copper vortex loss and the coil end height in the motor (Example) having the stator of the present invention and the motor (Comparative Example) having the stator of the conventional structure]
The inventors of the present invention are, for example, a motor (comparative example) including a stator having a conventional structure disclosed in Patent Document 2 (a coil having a rectangular wire) and a stator having a structure shown in FIG. A motor having a stator having a divided conductor connection structure shown (Example 1), a motor having a stator having a divided conductor connection structure shown in FIG. 3 (Example 2), and a divided conductor connection structure shown in FIG. Each model of a motor (Example 3) having a stator having the above was created in a computer, and an analysis was performed comparing the copper vortex loss and the height of the coil end.

In this analysis, the conductor of the circular cross section has a diameter of φ1 mm, the rectangular wire has a rectangular cross section of 1 mm × 1.5 mm, the copper wire resistivity is 1.67 μΩcm, the carrier frequency is 5 kHz, and the rotor rotational speed is 6000 Hz. The torque was constant. The analysis results are shown in Table 1 below.

In Table 1, the copper vortex loss, the coil end height, and the connection portion resistance are normalized to 1 for the analysis result of the comparative example, and the results of Examples 1 to 3 are shown as ratios relative to this comparative example.
From Table 1, it was proved that the copper vortex loss was reduced by about 5% in both Examples 1, 2, and 3 as compared with the comparative example.

  This is because the entire coil in the comparative example is formed from a rectangular wire having a large cross-sectional dimension, and the conductor area facing the slot opening is large, so that the copper vortex loss generated in the rectangular wire is smaller than in each example. This is due to the fact that it is relatively large and leads to loss due to heat generation of the coil.

  Moreover, when the copper wire for coils exhibited the connection structure mentioned above, the increment of the height of a coil end when this connection part was distribute | arranged to the coil end was confirmed in the computer model.

  From Table 1, Example 1 including the coil having the connection structure 30 shown in FIG. 2 has a height increase of about 30%, while having the connection structure 30A shown in FIG. 3 and the connection structure 30B shown in FIG. In Examples 2 and 3 including the coil, the height is increased by about 10%, and in Examples 2 and 3, an increase in the height of the coil end is remarkably suppressed.

  Further, with respect to the connection portion resistance ratio, Example 3 stayed at 5% increase compared to 10% increase of Example 2, and the effect of making the end face of the split conducting wire uneven was demonstrated.

  From the above analysis results, the torque performance was excellent while suppressing the increase in the size of the coil end as much as possible by using a stator having a coil composed of a coil conductor having the connection structure and conductor arrangement shown in the figure. A motor can be obtained.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

DESCRIPTION OF SYMBOLS 10 ... Stator core, 11 ... Teeth, 12 ... Yoke, 13 ... Slot, 13a ... Slot opening, 20 ... Coil conductor (single conductor), 21 ... Flat wire (divided conductor), 22 ... Circular section conductor (divided) Conductive wire), 21 ', 22' ... Uneven surface, 30, 30A, 30B ... Connection structure, 40 ... Conductive member, 50 ... Crimp terminal, 100 ... Stator

Claims (5)

A stator having a substantially annular or arcuate yoke in plan view and teeth projecting radially inward from the yoke, wherein a coil is formed by winding a conductor around the teeth. ,
The coil is composed of a single conducting wire in which two or more types of divided conducting wires having different cross-sectional dimensions are connected, and the divided conducting wire having a relatively small cross-sectional dimension is disposed on the radial front end side of the teeth. Stator.   Both ends are abutted via a conductive member, a crimp terminal is arranged around the end and the conductive member, and the divided conductors are connected to each other in a posture in which the crimp terminal is crushed. The stator according to claim 1.   The stator according to claim 2, wherein, of the divided conducting wires, the end portion that is abutted with the conductive member has an uneven surface.   The two or more types of divided conductors having different cross-sectional dimensions, wherein the divided conductor wound around the yoke side of the teeth is a flat wire, and the divided conductor on the radial tip side of the teeth is a conductor having a circular cross section. The stator in any one of 1-3.   A motor comprising the stator according to claim 1 and a rotor rotating inside the stator.

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