JP4539216B2 - Stator shape of switched reluctance motor - Google Patents

Description

  The present invention relates to a stator shape of a switched reluctance motor suitable for use in a vehicle or the like.

A switched reluctance motor uses a magnetic saliency of a plurality of salient pole portions provided on a rotor to rotate the rotor by a rotating magnetic field and does not use a permanent magnet for the rotor. Since this structure is simple and does not use a permanent magnet, it can be rotated at a high speed, can be used in a high temperature environment, and is inexpensive.
Such a switched reluctance motor is, for example, as shown in Patent Document 1. A bobbin (insulator) in which a recess is provided in a tooth constituting a stator of a switched reluctance motor and a winding is wound around the recess. ) Is inserted. The bobbin is provided with a convex portion at a position corresponding to the concave portion, and the winding is fixed to the tooth via the bobbin by fitting the concave portion and the convex portion to each other.

Conventionally, the shape of the portion of the tooth of the switched reluctance motor excluding the back yoke portion is straight, that is, a shape extending linearly so that there is no unevenness in the circumferential direction and the circumferential width is the same in the radial direction. However, it is known that it is preferable in suppressing leakage magnetic flux and preventing magnetic saturation. However, in order to fix the winding wound around the teeth so as not to drop to the inner peripheral side, it is necessary to provide a recess in the shape of the teeth as described above.
JP 2002-78272 A

However, in such a structure, since the magnetic path width is limited by providing the recess in the teeth, the magnetic flux generated by energizing the winding is also limited, and the conventional structure having straight teeth. As compared with the switched reluctance motor, the problem arises that the generated torque becomes small.
On the other hand, in the permanent magnet type synchronous motor, in order to increase the torque, the circumferential width of the innermost end of the teeth is generally wider than the portion where the winding is applied. Although it is locked and does not fall off, when such a shape is applied to the teeth of a switched reluctance motor, the generated torque decreases for the following reasons.

  FIG. 9 (a) shows a straight tooth of a general switched reluctance motor, and FIG. 9 (b) shows that the circumferential width W1 of the innermost circumferential end is compared with the circumferential width W2 of the portion to be wound. The teeth having a widened shape are shown. Here, the circumferential width indicates the length in the direction perpendicular to the circumferential center C of the teeth (coincident with the radial direction of the stator). The torque generated when these teeth are applied to a switched reluctance motor will be described below.

FIG. 10 shows the magnetic flux Ψ [Vs] interlinked with the windings when I [A] is supplied as a phase current to the windings of the respective teeth. In FIG. 10, ◇ indicates the data of the teeth having a straight shape excluding the back yoke shown in FIG. 9A, and black △ indicates the circumferential width of the innermost end shown in FIG. 9B. The data of the teeth which expanded is shown. A line segment OA having a small inclination is a characteristic at a non-opposing position of the rotor, and a line segment OB having a large inclination is a characteristic at the opposing position of the rotor.
Here, the facing position of the rotor indicates a case where the circumferential center of the salient pole portion of the rotor is completely coincident with the circumferential center of the tooth to be energized (see FIG. 6 described later). The non-opposing position of the rotor means a case where the circumferential center of two salient pole portions adjacent to the rotor completely coincides with the circumferential center of the tooth to be energized. (See Fig. 4 below)

  The I-Ψ characteristic (line segment OA) at the non-opposing position of the rotor increases substantially linearly with the increase of the phase current, but its inclination is small. This is because the air gap between the teeth and the rotor is large at the non-facing position, so that even if the phase current is increased, the magnetic resistance in the air gap is large and it is difficult to generate magnetic flux. Further, the slope of the I-Ψ characteristic (line segment OA) in the tooth (black line Δ) having the shape shown in FIG. 9B is the I-Ψ of the tooth (◇) having the shape shown in FIG. The larger characteristic is that the circumferential width of the innermost peripheral end of the teeth is wide, and a large amount of leakage magnetic flux is generated toward the salient pole portion of the rotor that is not opposed thereto.

  On the other hand, since the air gap between the rotor and the teeth is minimized at the position facing the rotor, the slope of the I-Ψ characteristic (line segment OB) increases in a small current region. When the magnetic flux Ψ reaches the saturation magnetic flux density of the electrical steel sheet used for the teeth and the rotor, the slope of the I-Ψ characteristic (line segment OB) becomes smaller at higher phase currents. The magnetic flux in the teeth (black triangle) having the shape shown in FIG. 9B is larger than the magnetic flux in the teeth (◇) having the shape shown in FIG. Although the leakage magnetic flux toward the pole portion is generated, it is somewhat larger, but the difference is negligible compared to the difference at the non-opposing position.

  Now, it is known that when the maximum current Imax is applied to this tooth, the torque generated by the switched reluctance motor is proportional to the area of the irregular triangle OAB. Therefore, as is apparent from this figure, the switched reluctance motor, of course, should adopt straight teeth (◇) generally used for the switched reluctance motor shown in FIG. This is desirable in terms of securing the generated torque, and it can be seen that the generated torque decreases when the circumferential width of the innermost peripheral end of the tooth is wide. (The smaller the torque generated at the rotor other than the salient pole part of the attracting rotor, that is, the smaller the leakage flux, the better)

  Note that the tooth shown in FIG. 9 (b) is the smallest width that the winding can lock the circumferential width of the innermost end compared to the tooth generally used in the permanent magnet type synchronous motor. The teeth are narrowed to the limit, and the teeth generally used for permanent magnet synchronous motors are actually wider than the illustrated width. When this tooth is applied to a switched reluctance motor as it is, the generated torque is further reduced.

  For the above reasons, it can be seen that if there is a recess in the portion other than the back yoke portion of the teeth, the magnetic flux is limited, and if there is a projection, leakage magnetic flux is generated, which is not preferable. It can also be seen that the shape of the teeth that maximizes the magnetic flux and has little leakage magnetic flux is a straight shape, and the circumferential width of the teeth is preferably equal to the circumferential width of the rotor salient poles.

  An object of the present invention is to solve the above-described problems based on the knowledge described above, and even if a structure that can lock the winding is provided on the innermost peripheral side of the teeth, a leakage magnetic flux is generated to generate torque. It is to provide a stator shape of a switched reluctance motor without reducing the above.

The stator shape of the switched reluctance motor of the present invention is a switched reluctance motor including a stator having a plurality of teeth and a rotor having a plurality of salient pole portions located on the inner peripheral side of the stator. The back yoke portion, the winding winding portion, and the winding locking portion located on the inner peripheral side of the winding winding portion, and this winding locking portion can lock the winding. A circumferential portion of the teeth having a convex portion protruding in the circumferential direction and having a circumferential center between the opposed circumferential side surfaces of the salient pole portions of the plurality of adjacent rotors facing each other between the circumferential side surfaces. When it coincides with the center of the direction, the projecting portion of the winding locking portion passes through the circumferential end of the innermost circumferential end surface of the teeth, and the circumferential side end faces the circumferential end. Before parallel plane And forming so that the range of the tooth side.

According to the stator shape of the switched reluctance motor described above , although the winding locking portion having the projecting portion protruding in the circumferential direction enabling locking of the winding is formed on the innermost peripheral side of the tooth, At the innermost peripheral end of the line locking portion, the circumferential width is made narrower than the circumferential width of the winding locking portion including the convex portion, so that the leakage magnetic flux increases at the non-opposing position of the rotor. And the reduction of the generated torque resulting from it can be suppressed as much as possible.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing a stator shape of a switched reluctance motor according to the present invention.
Here, a three-phase (U-phase, V-phase, W-phase) switched reluctance motor in which windings are applied to each tooth by concentrated winding is shown.
The stator 1 is configured by arranging four teeth, that is, twelve teeth, U1 to U4, V1 to V4, and W1 to W4 for the same phase so that the circumferential side surfaces of the back yoke portion are in contact with each other. Yes. Also, windings U1c to U4c, V1c to V4c, and W1c to W4c are wound by concentrated winding on each of the teeth U1 to U4, V1 to V4, and W1 to W4, and the same phase windings are connected in series. Or they are connected in parallel. On the other hand, the rotor 2 has eight salient pole portions and is connected to the shaft 3 to output torque generated at the salient pole portions. The teeth U1 to U4, V1 to V4, W1 to W4 of the stator 1 and the rotor 2 are formed by punching, for example, a 0.35 mm thick electromagnetic steel sheet into a shape shown in the figure, and laminating it in the central axis direction of the stator. Has been. In addition, the thickness of an electromagnetic steel plate is not limited to this.
In the following, the shape and operational effects of the U-phase teeth will be described. (The shape and operational effects of the V-phase and W-phase teeth are the same, and the description is omitted.)

FIG. 2 is a schematic cross-sectional view showing the U-phase tooth U1 shown in FIG.
The teeth U1 are formed of a back yoke portion 4, a winding winding portion 5, and a winding locking portion 6 located on the inner peripheral side of the winding winding portion 5. The winding locking portion 6 While having the convex part 7 which protrudes in the circumferential direction which can lock the coil | winding U1c, the circumferential width W1 of the innermost peripheral side end of the coil | winding latching part 6 is set to the convex part of the said coil | winding latching part 6. 7 is made narrower than the circumferential width W2 of the portion provided .

The back yoke portion 4 is a portion that becomes an outer peripheral magnetic path of the magnetic flux generated by the winding U1c, and also serves to mechanically connect adjacent teeth. The winding winding part 5 has the same circumferential width at any position in the radial direction, and the winding U1c is wound around the circumference. Since the winding U1c improves the space factor of the winding, here, a rectangular enamel-coated copper wire having a square cross section is used. Next, the winding locking portion 6 is provided with a convex portion 7 protruding in the circumferential direction. The circumferential width W2 of the winding locking portion 6 provided with the convex portion 7 is made wider than the circumferential width W3 of the winding winding portion 6 so that the winding U1c does not fall off to the inner peripheral side. is doing. Moreover, this convex part 7 is formed so that the circumferential direction width | variety may become narrow as it goes to the innermost peripheral side end of teeth U1.
Here, the circumferential width indicates the length in the direction perpendicular to the circumferential center C1 of the teeth (coincident with the radial direction of the stator).

FIGS. 3A and 3B are schematic perspective views showing in detail the form of the teeth U1 shown in FIG. Here, the teeth U1 are formed by laminating the electromagnetic steel plates 8 having a thickness of 0.35 mm in the direction of the central axis of the stator, and as shown in FIG. It plays the role which latches toward outward from the radial inside.
As shown in FIGS. 1 to 3, in a split core type stator in which teeth having a substantially T-shape are arranged with their back yoke portions in contact with each other to form a stator, the winding U1c is directly connected to the teeth U1. Since aligned winding is possible, there is an advantage that the space factor of the winding can be improved. Before winding the winding U1c, by winding or sticking insulating paper (not shown) around the winding winding portion 5 of the tooth U1, the wound winding U1c and the tooth U1 Ensures electrical insulation.

Next, the shape of the convex portion in the winding locking portion in this embodiment will be described.
FIG. 4 is a schematic cross-sectional view in a plane perpendicular to the central axis of the stator, showing the range of formation of the convex portion in the winding locking portion.
In FIG. 4, the relationship between the teeth U1 and the salient pole portions 9 of the rotor 2 is in a non-opposing position. The non-opposing position means that the circumferential center C1 of the tooth U1 is the farthest from the salient pole portion 9 of the rotor 2, that is, the circumferential center C2 of the two adjacent salient pole portions 9 and the circumferential center C1 of the tooth U1. It shall indicate the matching state.
Further, the circumferential side surface of the salient pole portion 9 of the rotor 2 is connected to the circumferential end of the outer circumferential surface of the salient pole portion 9 shown in a in FIG. 4 and the innermost circumferential end of the salient pole portion 9 shown in b. It is a plane ab. In addition, the salient pole part 9 of the rotor 2 shall be formed in the shape which makes the circumferential direction width | variety protrude in the radial direction outward of a rotor.

Formation range of the convex portion 7 in the windings locking section 6, the tooth side of the plane parallel de in the circumferential direction side of the circumference Direction through the end e the circumferential end e side of the innermost end surface of the teeth U1 The range is U1 . In other words, the convex portion 7 in the winding engagement portion 6 is formed within the hatching in FIG. 4 which is surrounded by the planar ce and plan de. Here, the plane ce is a plane obtained by extending the circumferential side surface of the winding portion 5 in the tooth U1 to the innermost peripheral side end of the tooth U1.
According to the above configuration, the leakage magnetic flux that leaks from the teeth U1 toward the plane ab that is the circumferential side surface of the salient pole 9 of the rotor 2 can be reduced, and the tendency to decrease the generated torque is suppressed as much as possible. Can be locked to.

Furthermore, the circumferential width W1 of the innermost circumferential end of the winding locking portion 6 shown in FIG. 2 is made the same as the circumferential width W3 of the winding winding portion 5 .
According to this, the magnetic path cross-sectional area in the winding part 5 and the magnetic path cross-sectional area at the innermost peripheral end of the tooth U1 become the same, and the winding magnetic flux is effectively linked to the rotor, Can be reduced.

FIG. 5 is a graph showing the effect of the switched reluctance motor according to the present invention.
Hereinafter, the effect of the present embodiment will be described with reference to FIG.
A square indicates the I-Ψ characteristic of the present embodiment. In order to show the effect, the circumferential width including the convex portion of the winding locking portion described above is the same from the position adjacent to the winding portion to the innermost peripheral end of the tooth, FIG. 9B. The I-Ψ characteristics of the teeth having the shape shown in FIG.
First, the line segment OA which is the I-Ψ characteristic at the non-opposing position of the rotor will be described. This is because when the positional relationship between the stator 1 and the rotor 2 is shown in FIG. 1, that is, when the U-phase teeth U1 to U4 and the salient poles of the rotor 2 are in a non-opposing position relationship. The relationship between the phase current I when the phase current I is applied to U1c to U4c and the magnetic flux Ψ interlinked with the winding at that time is shown.

According to the present embodiment, the circumferential width of the innermost peripheral end of the winding latching portion is made narrower than the circumferential width of the portion where the convex portion of the winding latching portion is provided. It can be confirmed that the leakage magnetic flux can be reduced and the inclination of I-Ψ can be reduced as compared with the teeth having the shape shown in FIG.
Next, the line segment OB which is the I-Ψ characteristic at the position facing the rotor will be described. This is because, when the positional relationship between the stator 1 and the rotor 2 is shown in FIG. 6, that is, when the U-phase teeth U1 to U4 and the salient poles of the rotor 2 are in the opposing position relationship, the U-phase winding U1c. It shows the relationship between the phase current I when the phase current I is supplied to .about.U4c and the magnetic flux .PSI.

Since the air gap between the U-phase teeth and the rotor is minimized at the position facing the rotor, the inclination is large in the region where the phase current is small. And when the saturation magnetic flux density of the electrical steel sheet used for the teeth and the rotor is reached, the slope becomes smaller at a phase current higher than that. The I-Ψ characteristic (□) in the present embodiment has a small magnetic flux Ψ due to a small amount of leakage magnetic flux, but is negligible compared to the difference at the non-opposing position.
As described above, it is known that the torque generated by the switched reluctance motor when the maximum current Imax is applied is proportional to the area of the irregular triangle OAB. Therefore, it is confirmed from FIG. it can.
In this embodiment, a rectangular wire having a rectangular cross-sectional shape is used as the winding, but a round wire having a more general cross-sectional shape can also be used. A small R portion may be provided.

FIG. 7 is a schematic perspective view showing another embodiment of the stator shape of the switched reluctance motor according to the present invention.
The teeth U1 shown in FIG. 3A are configured by laminating a required number of electromagnetic steel plates punched by pressing in the stator central axis direction so as to have a convex shape constituting the convex portion of the winding locking portion. However, in the teeth of the embodiment shown in FIG. 7, the teeth U1 are formed by laminating a plurality of electromagnetic steel plates, and among the plurality of electromagnetic steel plates constituting the teeth, some of the electromagnetic steel plates 8a include the convex shape 8c forming the convex portion 7 is provided, along with not provided the convex Additional electrical steel sheet 8b, placing the previous SL part of the electromagnetic steel plates 8a at both ends of the central axis line direction of the stator.

  In this way, the convex portion 7 of the winding locking portion is configured only by the convex shape 8c provided on some of the electromagnetic steel plates 8a, and the convex shape is not provided on the other electromagnetic steel plates 8b. The ratio of the electromagnetic steel sheet 8a provided with 8c to the entire electromagnetic steel sheet is reduced to further effectively reduce the leakage magnetic flux from the teeth to the salient pole portion of the rotor at the non-opposing position, thereby suppressing the torque reduction due to the leakage magnetic flux. be able to. Of course, it is needless to say that the convex portion 7 needs to have a strength necessary for locking the winding.

Further, by disposing the magnetic steel sheet 8a having an equivalent said portion of convex 8c at both ends of the central axis line direction of the teeth, protrusions 7 to be provided at both ends of the central axis line direction of the teeth U1 Therefore, when the winding U1c is locked, the span length of the locking point can be increased as much as possible, and the winding is balanced compared to the case where the locking point is provided in the middle portion in the central axis direction. It can be locked more firmly.
In the above embodiment, the teeth are configured by laminating magnetic steel sheets, but by integrally forming the teeth with a powder magnetic material and forming the same shape as the teeth shown in FIG. 3 or FIG. Similar effects can be obtained.

FIG. 8 is a schematic cross-sectional view showing still another embodiment of the stator shape of the switched reluctance motor according to the present invention.
As shown in FIG. 8, the teeth U1 are formed of a back yoke portion 4, a winding winding portion 5, and a winding locking portion 6 located on the inner peripheral side of the winding winding portion 5. The winding latching portion 6 has a convex portion 7 projecting in the circumferential direction that can latch the winding U1c, and the circumferential width W1 of the innermost circumferential side end of the winding latching portion 6 is set to the winding. The locking portion 6 is narrower than the circumferential width W2 of the portion where the convex portion 7 is provided .
Formation range of the convex portion 7 in the windings locking section 6, the tooth side of the plane parallel de in the circumferential direction side of the circumference Direction through the end e the circumferential end e side of the innermost end surface of the teeth U1 The range of U1 is a minimum size within the range .
Furthermore, the circumferential width W1 of the innermost circumferential side end of the winding latching portion 6 is made equal to the circumferential width W3 of the winding winding portion 5 .

As shown in FIG. 8, the convex shape can be arbitrarily formed within the hatched range shown in FIG. 4, and if the strength for locking the winding can be secured, the leakage flux is suppressed. In order to suppress a reduction in torque, it is preferable to make the convex portion 7 as small as possible .

  In addition, this invention is not limited only to the said embodiment, Many deformation | transformation or a change is possible.

  The stator shape of the switched reluctance motor of the present invention is suitable for use in a switched reluctance motor with higher reliability with respect to locking and fixing of the winding.

It is a schematic cross section which shows one Embodiment of the stator shape of the switched reluctance motor which concerns on this invention. It is a schematic cross section which shows one Embodiment of the stator shape of the switched reluctance motor which concerns on this invention. It is a model perspective view which shows one Embodiment of the stator shape of the switched reluctance motor which concerns on this invention. It is a schematic cross section in the plane perpendicular to the central axis of the stator showing the formation range of the convex portion in the stator-shaped winding locking portion of the switched reluctance motor according to the present invention. It is a graph which shows the magnetic flux linked to a coil | winding when supplying a phase current to the coil | winding of each tooth | gear in the switched reluctance motor which concerns on this invention. It is a schematic cross section which shows one Embodiment of the stator shape of the switched reluctance motor concerning this invention in the opposing position of a rotor. It is a model perspective view which shows other embodiment of the stator shape of the switched reluctance motor which concerns on this invention. It is a schematic cross section which shows other embodiment of the stator shape of the switched reluctance motor which concerns on this invention. It is a schematic cross section which shows the stator shape of the conventional switched reluctance motor. It is a graph which shows the magnetic flux linked to a coil | winding when a phase current is supplied to the coil | winding of each tooth | gear in the conventional switched reluctance motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stator 2 Rotor 3 Shaft U1 Teeth 4 Back yoke part 5 Winding winding part 6 Winding latching part 7 Convex part 8 Electrical steel sheet 9 Salient pole part

Claims (6)

In a switched reluctance motor comprising a stator having a plurality of teeth and a rotor having a plurality of salient pole portions located on the inner peripheral side of the stator,
The teeth are formed of a back yoke portion, a winding winding portion, and a winding locking portion located on the inner peripheral side of the winding winding portion. The winding locking portion locks the winding. While having a projecting portion protruding in the circumferential direction to enable,
When the circumferential center between the respective circumferential side surfaces facing each other of the salient pole portions of the plurality of adjacent rotors coincides with the circumferential center of the teeth facing between the circumferential side surfaces, The convex portion of the winding locking portion passes through the circumferential end of the innermost circumferential end surface of the teeth, and is in the range on the teeth side from a plane parallel to the circumferential side surface facing each circumferential end. A stator shape of a switched reluctance motor characterized by being formed as follows. 2. The stator shape of the switched reluctance motor according to claim 1, wherein the convex portion is formed so that a circumferential width becomes narrower toward an innermost peripheral end of the teeth . The stator shape of the switched reluctance motor according to claim 2 , wherein an end surface of the convex portion is formed to be on the parallel plane . The switched width according to any one of claims 1 to 3 , wherein a circumferential width of an innermost circumferential end of the winding locking portion is made equal to a circumferential width of the winding winding portion . The stator shape of a reluctance motor. Among the plurality of magnetic steel sheets constituting the teeth, claims a part of the electromagnetic steel plates, characterized in that it is provided with the convex shape to a convex shape is provided, other electromagnetic steel plates forming the convex portion 1 The stator shape of the switched reluctance motor according to any one of? The stator shape of the switched reluctance motor according to claim 5, wherein the part of the electromagnetic steel plates is disposed at both ends of the stator in the central axis direction.

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