JP2009077491A - Stator core laminated body and electric motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stator core laminated body in which a plurality of steel sheets are integrally laminated by welding and the like while the occurrence of iron loss is suppressed without enlarging an outline size and to provide an electric motor. <P>SOLUTION: A projection 40 erected toward a center axis from a core body 22 is arranged between adjacent salient poles 24. A groove-like recess 42 is formed at a tip of the projection 40. An inner face of the recess 42 is welded and a plurality of electromagnetic steel sheets 21a are bonded. It is desirable that height A from a reference circle of the core body 22 to the tip of the projection 40 is 50% or less of height B from the reference circle of the core body 22 to a tip of the salient pole 24. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a stator core laminate and a motor.

  In general, a switched reluctance motor (hereinafter referred to as an “SR motor”) that is an electric motor has a stator that is internally fitted and fixed to a stator case, and a rotor that is rotatably provided to the stator.

  The stator case is generally cylindrical, and the core body is fitted and fixed to the inner periphery of the cylindrical portion. Moreover, the opening part of the both ends of a stator case is obstruct | occluded by the front bracket and the rear bracket, respectively. Each bracket is provided with a bearing at the center in the radial direction, and the shaft of the rotor is rotatably supported by the bearing.

  The rotor has a structure in which a shaft is press-fitted into the inner diameter of a rotor core having a plurality of salient poles projecting at right angles to the rotation axis. The stator has a structure in which coils are arranged around salient poles of the stator core laminate. The stator core laminate includes a substantially cylindrical core body and a plurality of salient poles standing from the core body toward the central axis.

The stator of such an SR motor is formed by laminating thin electromagnetic steel plates in order to suppress the occurrence of iron loss due to eddy currents. At this time, fastening by welding is performed in order to fix the laminated electromagnetic steel sheets. However, when the magnetic flux flow path of the stator is narrowed for welding, the magnetic flux density is increased and a lot of iron loss is generated. In view of this, there has been proposed a method in which a protrusion that hardly flows magnetic flux is provided outside the stator and welding is performed at the protrusion (see, for example, Patent Document 1).
JP-A-5-316709

  However, when a protrusion is provided outside the stator as in Patent Document 1, there is a problem that the outside dimension of the stator becomes large and the outside dimension of the entire SR motor also becomes large.

  Accordingly, the present invention has been made in view of the above-described circumstances, and provides a stator core laminate and a motor in which a plurality of steel plates are joined without increasing the outer dimensions while suppressing the occurrence of iron loss. To do.

In order to solve the above-described problems, a stator core laminate according to the present invention is formed by laminating a plurality of steel plates, and has a substantially cylindrical core main body and a plurality of erected from the core main body toward the central axis. A stator core laminated body for a motor including salient poles, comprising a protruding portion erected from the core body toward a central axis between the adjacent salient poles, and the plurality of steel plates are It is characterized by being joined at the protrusion.
According to this configuration, since the plurality of steel plates are joined at a position deviating from the core body serving as a magnetic flux flow path (magnetic path), iron loss can be prevented without eroding the magnetic path. In addition, since the protrusion is provided inside the core body, the outer diameter of the stator core laminate is not increased.

The height from the reference circle of the core body to the tip of the protrusion is 50% or less of the height from the reference circle of the core body to the tip of the salient pole.
According to this configuration, a balance between the iron loss of the stator and the output torque of the motor can be ensured. In addition, it is possible to secure a coil arrangement space around the salient pole, and the coil space factor can be improved.

In addition, both side surfaces of the salient poles in the circumferential direction of the core body are formed in parallel to each other, and side surfaces of the protrusions are formed in parallel with side surfaces of the adjacent salient poles. .
Further, the inner surface of the core main body that is continuous with the side surface of the salient pole is formed by a plane perpendicular to the side surface of the salient pole.
According to these configurations, the cross-sectional shape of the coil arrangement space can be made into a substantially square shape or a substantially rectangular shape. Thereby, it becomes easy to mount the coil whose cross-sectional shape is wound in advance in a substantially square shape or a substantially rectangular shape, and the space factor of the coil can be improved.

The minimum value of the width of the core body in the radial direction is 55% or more of the width of the salient pole in the circumferential direction of the core body.
According to this configuration, the magnetic flux density of the core body becomes smaller than the magnetic flux density of the salient pole, and the magnetic flux leaks only from the salient pole without leaking from the core body. Therefore, the output of the motor can be improved.

In addition, a recess extending in the axial direction of the core body is formed at the tip of the protrusion, and the plurality of steel plates are joined by welding the inner surfaces of the recess.
According to this configuration, the welding area can be increased by welding the inner surface of the concave portion, and a plurality of steel plates can be strongly joined to increase the strength of the stator core laminate.

Further, the plurality of steel plates are joined by fitting convex portions and concave portions formed on the protruding portions.
According to this configuration, it becomes possible to easily join a plurality of steel plates without depending on welding, simplify the manufacturing process, and reduce the manufacturing cost.

On the other hand, a motor according to the present invention includes a stator in which a coil is disposed around the salient poles in the stator core laminate described above, and a rotor that is coaxially disposed inside the stator. And
According to this configuration, since the stator core laminated body in which the iron loss is suppressed is provided, a highly efficient motor can be provided. Moreover, since the stator core laminated body with a small external shape is provided, a small motor can be provided.

  According to the present invention, it is possible to provide a stator core laminate and a motor in which a plurality of steel plates are joined without suppressing the occurrence of iron loss and without increasing the outer dimensions.

(First embodiment)
A first embodiment of the present invention will be described. FIG. 1A is a perspective view of a switched reluctance motor, and FIG. 1B is a side sectional view taken along line FF in FIG. 2A is a front cross-sectional view taken along the line GG in FIG. 1B, and FIG. 2B is an enlarged view of a portion P in FIG. 2A.
As shown in FIG. 1B, a switched reluctance motor (hereinafter referred to as “SR motor”) 1 includes a cylindrical stator 20 that is internally fixed to a cylindrical stator case 2, and an inner side of the stator 20. And a rotor 10 that is rotatably provided. In addition, it has a front bracket 3 externally fixed to one end portion of the stator case 2 and a rear bracket 4 externally fixed to the other end portion.

The front bracket 3 and the rear bracket 4 are fixed to the stator case 2 with set bolts 5. At this time, as shown in FIG. 2A, a concave portion is provided on the inner peripheral surface of the stator case 2 and a concave portion is provided on the outer peripheral surface of the stator 20, and the set bolt 5 is passed through a hole 28 formed by these concave portions. It has a fixed structure.
Accordingly, the front bracket 3 and the rear bracket 4 can be fixed to the stator case 2 without increasing the outer diameter of the SR motor 1 shown in FIG. Rotation can be prevented.

  As shown in FIG. 1B, the rotor 10 is provided with a hole into which the shaft 11 is inserted, and the shaft 11 is press-fitted and fixed in this hole. The shaft 11 is rotatably supported by a front side bearing 6 disposed on the front bracket 3 and a rear side bearing 7 disposed on the rear bracket 4. As a result, the rotor 10 is pivotally fixed to the stator 20. The rotor 10 is formed by laminating electromagnetic steel plates. As shown in FIG. 2A, a plurality of rotor salient poles 14 are formed radially at right angles to the rotation axis of the rotor 10.

  As shown in FIG. 2A, the stator 20 has a structure in which a coil 50 is arranged around the salient poles 24 of the stator core laminate 21. The stator core laminate 21 is also formed by laminating electromagnetic steel plates. The stator core laminate 21 includes a substantially cylindrical core body 22 and a plurality of salient poles 24 standing from the core body 22 toward the central axis. A winding is wound around the side surface of the salient pole 24 to form a U-phase / V-phase / W-phase stator coil 50. The starting point and the ending point of each winding of the U-phase / V-phase / W-phase coil 50 wound around the salient pole 24 are taken out from the rear bracket 4 shown in FIG. Connected). Power supply to the U-phase, V-phase, and W-phase coils 50 is performed based on the rotational position information of the rotor 10 by the rotation sensor (resolver) 60. The rotation sensor 60 includes a resolver stator 62 fixed to the rear bracket 4 and a resolver rotor 61 fixed to the shaft 11 and rotating inside the resolver stator 62.

  As shown in FIG. 1B, the front bracket 3 is provided with a plurality of front side through holes 8, and the rear bracket 4 is provided with a plurality of rear side through holes 9. Further, a front side fan 18 and a rear side fan 19 are provided on both end faces of the rotor 10, respectively. When the fans 18 and 19 rotate together with the rotor 10, an axial flow is generated, and an air flow from the front side through hole 8 (rear side through hole 9) to the rear side through hole 9 (front side through hole 8) occurs. Thus, the stator coil 50 can be cooled.

(Stator core laminate)
FIG. 3 is a perspective view of the stator core laminate of the SR motor of the present invention.
The stator core laminate 21 is formed by laminating a plurality of electromagnetic steel plates 21a such as silicon steel plates. The stator core laminate 21 has a substantially cylindrical core body 22 and a plurality of salient poles 24 erected from the core body 22 toward the central axis. The core body 22 is configured by alternately arranging base portions on which salient poles 24 are erected and yoke portions connecting adjacent base portions in the circumferential direction. A recess for penetrating the set bolt is formed in the outer peripheral portion of the base portion.

  In addition, a mountain-shaped protrusion that protrudes in the center direction at a height lower than the height of the salient pole 24 is provided on the inner periphery of the yoke portion. That is, between the adjacent salient poles 24, the protrusion 40 is erected from the core body 22 toward the central axis. A recess 42 extending in the axial direction of the core body 22 is formed at the tip of the protrusion 40. By welding the inner surface of the recess 42, the plurality of electromagnetic steel plates 21a are joined.

  4A is a front view of the electromagnetic steel sheet, FIG. 4B is a perspective view, and FIG. 4C is an enlarged view of a Q portion in FIG. 4A. As shown in FIG. 4A, the height A from the reference circle of the core body 22 to the tip of the protrusion 40 is 50% or less of the height B from the reference circle of the core body 22 to the tip of the salient pole 24. It has become. The reference circle of the core body 22 is a circle at the minimum width (D) portion in the radial direction of the core body 22.

The height A of the protrusion 40 is determined by the balance between the iron loss of the stator and the output torque of the SR motor, and the space factor of the coil 50.
5A is a graph showing the relationship between the height of the protrusion and the torque, and FIG. 5B is a graph showing the relationship between the height of the protrusion and the maximum salient pole magnetic flux. ) Is a graph showing the relationship between the height of the protrusion and the minimum inductance value. 5 is the ratio of the height A of the protrusion 40 to the height B of the salient pole 24, and is 100% when A = B.

  According to FIG. 5A, the output of the SR motor is provided by providing the protrusion 40 as compared with the conventional technique without the protrusion 40 (“the ratio of the protrusion height to the protrusion height” = 0%). It can be seen that the torque increases. The torque of the SR motor has a property proportional to the magnitude of the magnetic flux flowing through the salient pole. As shown in FIG. 5B, the salient pole magnetic flux maximum value φmax is increased by providing the protrusion 40. This is because the magnetic flux density of the core body is reduced by providing the protrusions 40, and the magnetic flux from the stator salient poles to the core body (from the core body to the stator salient poles) easily flows. As a result, the output torque of the SR motor is increased.

  However, the torque decreases as the height A of the protrusion 40 increases. The torque of the SR motor also has a property that it is proportional to the inductance gradient that periodically changes depending on the rotor rotation angle. Here, the slope of the inductance generally decreases as the minimum value of the inductance increases. Since the magnetic resistance increases as the rotor salient pole 14 moves away from the stator salient pole 24, the inductance of the coil 50 becomes small. Become. However, if the protrusions 40 are present between the stator salient poles, the magnetic resistance decreases and the minimum value of inductance increases. And as shown in FIG.5 (c), the minimum value of an inductance will increase, so that the height A of the projection part 40 increases. As a result, the slope of the inductance decreases, and the torque decreases as shown in FIG.

  In the present embodiment, a protrusion is provided on the rotor body, and a concave portion of the protrusion is welded to join the electromagnetic steel sheets. Therefore, a large torque can be obtained as compared with the prior art in which no protrusion is provided.

  On the other hand, FIG.5 (d) is a graph which shows the relationship between the height of a projection part, and an iron loss. According to FIG. 5 (d), it can be seen that the iron loss of the stator is reduced by providing the protrusion 40 as compared with the conventional technique without the protrusion 40. In addition, the iron loss decreases as the height A of the protrusion 40 increases. From the results of FEM analysis, it has been confirmed that the magnetic flux density becomes lower toward the tip of the protrusion 40. It is considered that iron loss is reduced by joining a plurality of electromagnetic steel sheets in such a low magnetic flux density portion.

Thus, the iron loss of the stator and the output torque of the motor are in a trade-off relationship.
Further, as shown in FIG. 2A, it is apparent that the space factor decreases as the protruding portion 40 becomes higher because the arrangement space of the coil 50 decreases.
Therefore, in the present embodiment, the height A from the reference circle of the core body 22 to the tip of the protrusion 40 is set to 50% or less of the height B from the reference circle of the core body 22 to the tip of the salient pole 24. Thereby, the balance between the iron loss of the stator and the output torque of the motor can be ensured. In addition, it is possible to secure a space for arranging the coils, and the space factor can be improved.

  On the other hand, as shown in FIG. 2A, the arrangement space of the coil 50 around the salient pole 24 is substantially rectangular (substantially square or substantially rectangular) in a cross section perpendicular to the extending direction of the winding. Is formed. Specifically, as shown in FIG. 4A, both side surfaces 25, 25 of the salient pole 24 in the circumferential direction of the core body 22 are formed in parallel to each other. Further, as shown in FIG. 4C, the side surface 45 of the protrusion 40 is formed in parallel with the side surface 25 of the adjacent salient pole 24. Furthermore, the inner surface 23 of the core body 22 that is continuous with the side surface 25 of the salient pole 24 is configured as a plane perpendicular to the side surface 25 of the salient pole 24.

  By making each part of the stator core laminated body 21 have the above shape, the arrangement space of the coil 50 can be made substantially rectangular as shown in FIG. Thereby, it becomes easy to attach the coil whose cross-sectional shape is wound in advance in a substantially square shape or a substantially rectangular shape, and the space factor of the coil 50 can be improved. The coil may be formed by winding a winding around the salient pole 24 instead of mounting the coil whose cross-sectional shape is approximately square or approximately rectangular.

On the other hand, as shown in FIG. 4A, the minimum width D in the radial direction of the core body 22 is 55% or more of the width C of the salient poles 24 in the circumferential direction of the core body 22.
The magnetic flux flowing through the stator core laminated body 21 flows from one salient pole 24 to the base portion of the core body 22 and flows to the salient poles adjacent to both sides through the yoke portions adjacent to both sides thereof. That is, the magnetic flux flowing through one salient pole 24 is divided into two yoke parts adjacent to it and flows. Therefore, when the width C of the salient pole 24 is 1.0 and the width D of the narrowest portion (minimum width portion) in the yoke portion is 0.5, the salient pole 24 and the yoke portion The magnetic flux density is equivalent. In the present embodiment, the minimum width D of the yoke portion is 0.55. Thereby, the magnetic flux density of the yoke portion becomes smaller than the magnetic flux density of the salient pole 24, and the magnetic flux leaks from only the salient pole 24 toward the rotor salient pole without leaking from the yoke portion. Therefore, the output of the SR motor can be improved.

As described in detail above, the stator core laminated body according to this embodiment shown in FIG. 4A is provided with the protrusions 40 erected from the core body 22 toward the central axis between the adjacent salient poles 24. And a plurality of electromagnetic steel plates 21a are joined at the protrusion 40.
According to this configuration, since the plurality of electromagnetic steel plates 21a are joined at a position deviating from the core body 22 serving as a magnetic flux flow path (magnetic path), iron loss can be prevented without eroding the magnetic path. . Further, by providing the protrusion 40 on the inner side of the core body 22, the outer diameter of the stator core laminate 21 is not increased, and thereby the outer diameter of the SR motor 1 is not increased. Furthermore, by providing the protrusions 40 between the adjacent salient poles 24, it becomes possible to provide the protrusions 40 in a dead space that does not contribute to the arrangement of the coils 50, thereby preventing a decrease in the space factor of the coils 50. be able to.

Further, a groove-like recess 42 extending in the axial direction of the core body 22 is formed at the tip of the protrusion 40, and a plurality of electromagnetic steel plates 21a are joined by welding the inner surface of the recess 42.
According to this configuration, the welding area can be increased by welding the inner surface of the recess 42, the plurality of electromagnetic steel plates 21 a can be strongly joined, and the strength of the stator core laminate 21 can be increased. Moreover, the fall of the space factor of the coil 50 by the protrusion of welding can be prevented.

(Modification)
FIG. 6 is an explanatory diagram of a stator core laminate according to a modification of the first embodiment. Fig.6 (a) is a front view of an electromagnetic steel plate, FIG.6 (b) is the R section enlarged view of Fig.6 (a). In the first embodiment shown in FIG. 4 (a), one recess 42 is formed at the tip of the protrusion 40, but the modification shown in FIG. 6 (b) is different in that a plurality of recesses 46 are formed. ing. Note that detailed description of portions having the same configuration as in the first embodiment is omitted.

As shown in FIG. 6B, a plurality of (for example, two) recesses 46 are formed at the tip of the protrusion 40 of the electromagnetic steel plate 32a. By laminating the electromagnetic steel plates 32 a, a plurality of groove-shaped recesses 46 are formed at the tips of the protrusions 40. And the some electromagnetic steel plate 32a is joined by welding the inner surface of this some recessed part 46, respectively.
In this way, the welding area can be further increased by welding the inner surfaces of the plurality of recesses 46. Therefore, the plurality of electromagnetic steel plates 32a can be strongly coupled to increase the strength of the stator core laminate.

(Second Embodiment)
FIG. 7 is an explanatory diagram of a stator core laminate according to the second embodiment. Fig.7 (a) is a front view of an electromagnetic steel plate, FIG.7 (b) is a cross-sectional enlarged view in the HH line | wire of Fig.7 (a). In the first embodiment shown in FIG. 4A, the concave portion 42 is formed in the protrusion 40, but in the second embodiment shown in FIG. 7B, the boss convex portion 47 and the boss concave portion 48 are formed. Is different. Note that detailed description of portions having the same configuration as in the first embodiment is omitted.

As shown in FIG. 7B, a boss convex portion 47 is formed on one surface (the lower surface in FIG. 7B) 34 of the protrusion 40. A boss recess 48 is formed on the other surface (upper surface in FIG. 7B) 35 of the protrusion 40. The boss convex part 47 and the boss concave part 48 are formed in a columnar shape of the same size by press molding or the like.
The electromagnetic steel plates 33a are laminated and a boss convex portion 47 formed on one of the adjacent electromagnetic steel plates is fitted into a boss concave portion 48 formed on the other electromagnetic steel plate, so that a plurality of The electromagnetic steel sheet 33a is joined. Thereby, it becomes possible to join several electromagnetic steel plates 33a easily irrespective of welding, and can simplify a manufacturing process and can reduce manufacturing cost.

The present invention is not limited to the above-described embodiment, and includes various modifications made to the above-described embodiment without departing from the spirit of the present invention.
A plurality of electromagnetic steel plates need only be joined at the protrusions, and the specific joining method is not limited to the above embodiment. For example, a through hole may be formed in the protrusion and a plurality of electromagnetic steel plates may be joined with bolts and nuts.
In the above embodiment, the case where the present invention is applied to an SR motor has been described as an example. However, the present invention can also be applied to a brushless motor.

It is the perspective view and side sectional drawing of a switched reluctance motor. It is front sectional drawing and a partial enlarged view of a switched reluctance motor. It is a perspective view of the stator core laminated body which concerns on 1st Embodiment. It is the front view of the electromagnetic steel plate of the stator core laminated body which concerns on 1st Embodiment, a perspective view, and the elements on larger scale. It is a graph which shows the relationship between the height of a projection part, and the relationship of torque, an inductance minimum value, an iron loss, and a stator salient-pole magnetic flux maximum value. It is the front view and partial enlarged view of the electromagnetic steel plate of the stator core laminated body which concern on the modification of 1st Embodiment. It is the front view and partial enlarged view of an electromagnetic steel plate of the stator core laminated body which concern on 2nd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Switch reluctance motor (motor) 10 ... Rotor 20 ... Stator 21 ... Stator core laminated body 21a ... Electromagnetic steel plate 22 ... Core main body 24 ... Salient pole 25 ... Side surface 40 ... Projection part 42 ... Concave part 47 ... Boss convex part (convex part) 48 ... Boss recess (recess) 50 ... Coil

Claims (8)

A stator core laminate for a motor comprising a plurality of steel plates laminated, a substantially cylindrical core body, and a plurality of salient poles erected from the core body toward the central axis,
Between the adjacent salient poles, provided with a protruding portion erected from the core body toward the central axis,
The stator core laminate, wherein the plurality of steel plates are joined at the protrusions.   2. The height from the reference circle of the core body to the tip of the protrusion is 50% or less of the height from the reference circle of the core body to the tip of the salient pole. Stator core laminate. Both side surfaces of the salient poles in the circumferential direction of the core body are formed parallel to each other,
3. The stator core laminate according to claim 1, wherein a side surface of the projecting portion is formed in parallel with a side surface of the adjacent salient pole.   4. The stator core laminate according to claim 3, wherein an inner surface of the core body that is continuous with a side surface of the salient pole is configured by a plane perpendicular to the side surface of the salient pole.   The minimum value of the width in the radial direction of the core main body is 55% or more of the width of the salient pole in the circumferential direction of the core main body, according to any one of claims 1 to 4. Stator core laminate. A concave portion extending in the axial direction of the core body is formed at the tip of the protrusion,
The stator core laminate according to any one of claims 1 to 5, wherein the plurality of steel plates are joined by welding the inner surfaces of the recesses.   The stator core laminate according to any one of claims 1 to 5, wherein the plurality of steel plates are joined by fitting convex portions and concave portions formed on the protrusions. . A stator in which a coil is disposed around the salient pole in the stator core laminate according to any one of claims 1 to 7,
A rotor arranged coaxially inside the stator;
A motor comprising:

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