JP2009095189A - Split stator and motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a split stator which can improve the strength of a stator without lowering the manufacturing efficiency and can effectively prevent an eddy loss occurring in a connecting portion of split cores, which is a unique problem with the split stator, and also to provide a motor equipped with the same. <P>SOLUTION: In the side faces of opposite yokes of adjacent split cores, concave portions and convex portions are alternately formed in the height direction of the split cores. The concave portions and convex portions of the split cores are engaged with each other to form an annular stator core. In the yokes, slits 2 which are extended over the adjacent split cores are formed in the height direction of the split stator 100A. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a split stator and a motor including the split stator.

  In the automobile industry, with the aim of further improving the running performance of hybrid cars and electric cars, developments for driving motors with higher output, lighter weight, and smaller size are in progress every day. In addition, home appliance manufacturers have no choice but to develop further miniaturization and higher performance of motors incorporated in various home appliances.

  In order to improve the performance of the motor, a problem is how to reduce various losses generated in the motor. For example, after electric input, copper loss due to conductor resistance loss occurs in the coil constituting the motor, and iron loss (or high frequency iron loss) due to eddy current loss and hysteresis loss occurs in the rotor and stator, Depending on these losses, motor efficiency and torque performance will be reduced. This eddy current loss is a loss caused by a change in magnetic flux density with time, and the hysteresis loss is a loss caused by the magnitude of the magnetic flux density.

  By the way, as a stator core constituting the motor, there is a method of manufacturing a stator (divided stator) from a plurality of divided cores from the viewpoint of improving manufacturing efficiency including coil formation. In this split stator, coils are formed on the teeth of the split core, and the split cores are assembled to form an annular core unit. The core unit is inserted into a cylindrical body (casing), and the cylindrical body is baked. The split stator is manufactured by fitting. Here, FIG. 11 shows a split stator A (coil is not shown) formed by laminating electromagnetic steel plates, and FIG. 12 is a cross-sectional view of the yoke A1 and teeth a2. The split core a in which the coil a3 is formed around the teeth a2 is assembled in the circumferential direction, and the cylindrical body b is shrink-fitted around the outer periphery.

  In the conventional split stator shown in the figure, the split cores are assembled in the circumferential direction, and the outer periphery thereof is integrated by shrink fitting or the like, but the adjacent split cores are merely in contact with each other by a yoke. There is room for development to improve the integrity (strength) of the split stator.

  As a technique for improving the assembly strength between the split cores described above, a split stator having a configuration in which the steel plates of the split cores made of the steel plate laminates are alternately fitted is disclosed in Patent Document 1, and adjacent split cores are disclosed. Patent Document 2 discloses a split stator in which an Ω-shaped convex portion is provided on one end and an Ω-shaped concave portion that engages the other is provided on the other end.

JP 2000-78779 A Japanese Patent Application Laid-Open No. 2002-262496

  In the split stator disclosed in Patent Document 1, since it is a form in which one steel plate is alternately fitted, it takes a lot of labor and time to manufacture the split cores and to assemble the split cores, The production yield is inevitably lowered due to the inability to assemble. On the other hand, in the split stator disclosed in Patent Document 2, it takes time and labor to form the Ω-shaped concave portions and convex portions, and the manufacturing cost is inevitably increased.

  By the way, in general, in a divided stator, as shown in FIG. 12, eddy currents f due to leakage magnetic flux or the like are likely to be generated in the yokes between adjacent divided cores, and how the eddy current loss caused by this can be reduced. This is one of the important issues for improving the performance of a motor having a split stator having a core. On the other hand, by fitting the split cores as disclosed in Patent Documents 1 and 2, the contact area between the split cores increases, the magnetic resistance decreases, and the leakage magnetic flux between the split cores also decreases. Is done. However, this time, there arises a problem that a magnetic flux flows in a vertical steel plate having a smaller magnetic resistance than an air gap formed between the divided cores, and vortex loss occurs when the magnetic flux penetrates the steel plate.

  The present invention has been made in view of the above-described problems. In a split stator formed of a plurality of split cores, the strength of the stator can be improved without lowering the manufacturing efficiency. It is an object of the present invention to provide a split stator that can effectively suppress vortex loss that occurs at the connection between split cores, which is a problem, and a motor including the split stator.

  In order to achieve the above object, a split stator according to the present invention is a stator having an annular yoke and a plurality of teeth projecting radially inward from the yoke, and the stator core forming the stator has a circumferential direction. In the split stator formed of a plurality of split cores divided into two, the side surfaces of both yokes where the adjacent split cores face each other are alternately provided with concave portions and convex portions in the height direction of the split cores. An annular stator core is formed by fitting the concave and convex portions of both split cores.

  The split core constituting the split stator of the present invention may be formed from a steel plate laminate in which steel plates are laminated, or a magnetic powder in which a soft magnetic metal powder or a soft magnetic metal oxide powder is coated with a resin binder is added. You may form from the powder magnetic core formed by pressure forming. As a steel plate material constituting the steel plate laminate, electromagnetic steel plates, cold rolled steel plates (SPCC), hot rolled steel plates (SPHC), carbon steel (S45C), and the like can be used. The magnetic metal powder constituting the dust core includes iron, iron-silicon alloy, iron-nitrogen alloy, iron-nickel alloy, iron-carbon alloy, iron-boron alloy, iron-cobalt alloy. An alloy, an iron-phosphorus alloy, an iron-nickel-cobalt alloy, an iron-aluminum-silicon alloy, or the like can be used.

  In the split core of the present invention, concave portions and convex portions are alternately formed in the height direction of the split core on the side surface facing the yoke of another split core adjacent to the side surface of the yoke. When the split core is made of a steel sheet laminate, the height of each of the recesses and protrusions is the same as the thickness of several steel sheets, and when the core is made of a dust core. Are pressure-molded in a mold so that the concave and convex portions have the same height. In any case, from the viewpoints of avoiding damage to the convex portion due to the height (thickness) of the convex portion being too small and work efficiency when assembling the divided cores in the circumferential direction, the concave portion and the convex portion The height is determined.

  According to the above-mentioned split stator of the present invention, the split stator itself formed by fitting the split cores with both concave and convex portions can be improved in rigidity and manufactured with good assembly work efficiency. There is no reduction in efficiency.

  Further, as an embodiment of the above-described split core, it is formed by stacking small split cores having the same circumferential yoke width in the height direction of the split core, and a plurality of small split cores are provided. There is also a form in which the concave portions and the convex portions are formed on the side surfaces of the yoke of the split core by being alternately stacked in the stacking direction.

  In this embodiment, a plurality of small divided cores are stacked to form one divided core, and this stacked form is formed by alternately stacking in the stacking direction of the small divided cores. The concave portions and the convex portions described above are alternately formed on the side surfaces of the divided core.

  Here, the small divided core is composed of one tooth and a yoke having a predetermined arc length, and this yoke has an asymmetrical length on the left and right from the portion connected to the tooth. However, a predetermined number of cores having the same shape and the same size may be manufactured as the small divided cores. When laminating small division cores, the concave and convex portions are alternately formed in the lamination direction by laminating each small division core in the opposite direction and with only the teeth aligned in the height direction. Because it is done.

  In a preferred embodiment of the split stator according to the present invention, the yoke has a slit extending between adjacent split cores extending in the height direction of the split stator.

  In the split stator, an air gap is generated between the adjacent split cores. As described above, in the split stator that is formed by fitting the side surfaces of the adjacent split cores to each other with the concave portions and the convex portions, for example, the magnetic flux flowing from the teeth to the concave portion of the yoke has a smaller magnetic resistance than the air gap. It flows to the convex part of the adjacent core located above and below. This flow of magnetic flux in the vertical direction is also referred to as a transitional magnetic flux. When the split core is made of a steel plate laminate in which steel plates are laminated, eddy loss occurs due to the transit magnetic flux passing through the upper and lower steel plates.

  Therefore, in this embodiment, in order to reduce this eddy loss as much as possible, in order to reduce the area of the steel plate through which the transitional magnetic flux flowing in the vertical direction penetrates, the end of the split core is arranged in the height direction of the split core. An extending slit is formed.

  This slit can be provided about 2 to 4 per one joint portion of the split core, but the effect of reducing the vortex loss due to the increase in the number of slits, the decrease in rigidity of the split core due to the increase in the number of slits, The number is set in consideration of a decrease in processing efficiency.

  Further, in the embodiment in which the slits between the adjacent divided cores are formed in the yoke of the divided core formed by stacking the small divided cores described above, in the posture in which the plurality of small divided cores are stacked, When the slit provided on the side surface forming the convex portion of the small split core is the first split slit, and the slit provided on the side surface forming the concave portion on the opposite side is the second split slit, The split slit length is relatively longer than the second split slit length, and the first split slit and the second split slit communicate with each other in a posture in which the split cores are fitted together. A slit straddling between adjacent cores to be divided is formed.

  In this embodiment, for example, a plurality of small divided cores having the same shape and the same dimensions are stacked to form one divided core, and when the divided cores are assembled in the circumferential direction, a slit straddling between the divided cores is formed. In this configuration, all the slit widths are the same in the height direction.

  As a configuration for that, by keeping the length of the slit (first split slit) formed in the convex part of the split core longer than that of the slit (second split slit) formed in the concave part, When the split cores are assembled to each other, the width of the slit formed by the communication between the first and second split slits can be unified in the height direction of the split stator.

  In a preferred embodiment of the split stator according to the present invention, W2 / W1 is 0.00 when the slot width formed between adjacent teeth is W1 and the slit width between adjacent split cores is W2. It is characterized by being in the range of 3 to 0.6.

  Regarding the width of the slit and the width of the slot between the teeth as described above, if the slit width is long and about the slot width, the effect of reducing the vortex loss due to the above-described transitional magnetic flux is increased. The rigidity of the is greatly reduced.

  When the slot width is W1 and the slit width is W2, according to experiments by the present inventors, the problem of buckling becomes significant when W2 / W1 exceeds 0.6, and W2 / W1 is 0. If the ratio is less than .3, the effect of reducing the eddy loss due to the crossing magnetic flux cannot be sufficiently expected. Therefore, in this embodiment, W2 / W1 is set to 0.3 to 0 as an optimum range satisfying both problems and effects. .6 range.

  In the motor having the above-described split stator of the present invention, the split cores are firmly assembled, vortex loss caused by the flow of magnetic flux in the connecting portion can be effectively suppressed, and the manufacturing efficiency is also high. .

  As can be understood from the above description, according to the split stator of the present invention, when the split cores are fitted together, the overall rigidity is high, and when a slit is provided between the split cores, the core is further provided. Vortex loss that occurs between them can be suppressed. Furthermore, the split stator according to the present invention can form split cores and split stators by preparing a plurality of one kind of small split cores. Therefore, a highly rigid split stator can be manufactured at a low manufacturing cost. It becomes possible.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1a is a perspective view showing an embodiment of a split stator according to the present invention, and FIG. 1b is an enlarged perspective view of a small split core. 2 is a perspective view showing another embodiment of the split stator of the present invention, FIG. 3 is an enlarged perspective view of two adjacent split cores, and FIG. 4 is viewed from the IV direction of FIG. It is an arrow view. FIG. 5 is an analysis result comparing the stresses generated in the split core connecting portions of the split stator (Comparative Example 1) made of the conventional split core and the split stator (Example 1) of the present invention shown in FIG. These are the analysis results which compared the loss resulting from the stress which arises in the division | segmentation core connection part of each of the comparative example 1 and Example 1. FIG. FIG. 7 is an analysis result comparing the loss due to the transition magnetic flux between the split stator of the present invention shown in FIG. 1 (Example 1) and the split stator of the present invention shown in FIG. 2 (Example 2), and FIG. 8 shows the slit width. 5 is a graph for explaining the optimum range of the ratio of the slot width. FIG. 9 is a diagram for explaining an embodiment of a method for punching a split core from a steel plate, and FIG. 10 is an analysis result comparing loss due to a difference in a method for punching a split core from a steel plate. The divided stator shown in the figure is formed by assembling divided cores made of small divided cores obtained by laminating electromagnetic steel sheets, but the divided stator of the present invention is formed by assembling divided cores composed of dust cores. Of course, what is included is included.

  FIG. 1a shows an embodiment of a split stator according to the present invention. The divided stator 100 is formed by laminating a plurality of electromagnetic steel plates at a predetermined height to form one small divided core 10 as shown in FIG. 1b, and the upper and lower surfaces are alternately opposed to each other in the height direction of the divided stator. In this way, one split core having a concave portion and a convex portion is formed on both side surfaces thereof by laminating, and the split cores are integrated with each other by fitting both the concave portion and the convex portion in the circumferential direction. It is manufactured by shrink fitting with a cylindrical tube 20. Each of the small divided cores 10 includes one tooth 10b and a yoke 10a that extends asymmetrically on the left and right sides of the tooth 10b.

  The small divided core is formed by laminating a plurality of electromagnetic steel plates, and therefore, the manufacturing efficiency is remarkably increased and the manufacturing yield is improved as compared with the conventional form in which the electromagnetic steel plates are fitted one by one.

  FIG. 2 shows another embodiment of the split stator of the present invention. In this divided stator 100A, three slits 2 straddling between adjacent divided cores are formed at each divided core joining portion, and this slit 2 is formed so as to penetrate from the upper end to the lower end of the divided stator 100A. Yes. For example, two or three slits with a width of about 1 mm can be arranged on a yoke with a width of 10 mm.

  FIG. 3 is an enlarged view of two adjacent divided cores taken out from the divided stator 100A of FIG.

  The small divided core 10 has a yoke 10a that protrudes from the teeth 10b in a left-right asymmetrical arc shape, and a first slit 2a is formed at the end of the yoke having a relatively long protruding length. A second slit 2b is formed at the end of the short yoke, and the width: a1 of the first slit 2a is set longer than the width: a2 of the second slit 2b. In a posture in which the divided cores are fitted to each other, the first slit 2a and the second slit 2b communicate with each other to form the slit 2 having the width: W2.

  In addition, since the small divided cores 10 having the same shape and the same dimensions are alternately stacked, the slits 2 to be formed are divided stators as shown in FIG. 4 viewed from the IV direction in FIG. A constant width: W2 is ensured from the upper end to the lower end.

  The magnetic flux that flows from the teeth to the yoke flows up and down avoiding the air gap, and vortex loss occurs when passing through the electromagnetic steel sheet positioned in the up and down direction, but the slit 2 is formed in the split core connecting portion. As a result of dividing the steel plate area through which the magnetic flux penetrates into small areas, the generated eddy loss can be reduced as much as possible.

[Analysis and Results of Comparison of Stresses Generated at the Split Core Connections of the Divided Stator Consisting of Conventional Divided Cores (Comparative Example 1) and the Divided Stator of the Present Invention (Example 1) shown in FIG. 1]
The present inventors have formed a conventional split stator (Comparative Example 1) in which the connecting surfaces of the yokes of adjacent split cores are formed obliquely (having a predetermined angle with respect to the radial direction), and FIG. The split stator (Example 1) of the present invention to be shown was modeled, and the maximum stress generated at both connecting portions by the tightening force at the time of shrink fitting was obtained by analysis. Here, in the case of the comparative example 1, since the connecting surfaces of the yokes are formed obliquely, stress is concentrated at the end portions, and the maximum stress is generated.

  As a result of the stress analysis, as shown in FIG. 5, when the maximum stress of Comparative Example 1 was set to 100, the maximum stress of Example 1 was about 50%. Furthermore, as shown in FIG. 6, when the loss such as the iron loss in the yoke of Comparative Example 1 is set to 100, the loss of Example 1 is reduced to about 80%.

  In Comparative Example 1, there is a concern about the deterioration of the magnetic characteristics at the stress concentration portion of the yoke, the increase in iron loss resulting from this, and the problems of defects such as heat generation and buckling, while in Example 1, this problem is solved. It can be concluded that.

[Analysis and Results Comparing Loss Due to Transition Magnetic Flux of Divided Stator (Example 1) of the Present Invention Shown in FIG. 1 and Divided Stator (Example 2) of the Present Invention Shown in FIG. 2]
The present inventors confirmed the effect of the slit by comparing the loss due to the transition magnetic flux between the split stator (Example 1) shown in FIG. 1 and the split stator (Example 2) shown in FIG. 2 by analysis. In this analysis, three slits having the same width are modeled in the yoke.

  From FIG. 7 showing the result of the analysis, when the loss (vortex loss) due to the transition magnetic flux in Example 1 is set to 100, in Example 2, the loss is reduced to about 75%. This demonstrates that a large loss reduction effect can be obtained by forming a slit in the split core joint.

  Judging from the analysis result of FIG. 7, the effect of inserting a slit in the split core joint can be sufficiently expected, but on the other hand, a decrease in strength (rigidity) of the split stator itself due to the slit is a problem. Therefore, the present inventors specified the width of the slit as a ratio with the width of the slot formed between the teeth, and verified the optimum range of this ratio. Here, as shown in FIGS. 3 and 4, the slit width is W2 and the slot width is W1, and the ratio: W2 / W1 is changed to analyze the loss reduction due to the crossing magnetic flux and the respective changes in the split stator strength. Graphed on common coordinates. The result is shown in FIG.

  From FIG. 8, it is clear that both graphs have the opposite result depending on the magnitude of W2 / W1, but as a result of the verification, the slit width is too long in the region where W2 / W1 exceeds 0.6, and it is local. It has been specified that the split stator is likely to be damaged such as buckling, and that in the region where W2 / W1 is less than 0.3, the slit width is too short and a vortex loss reduction effect cannot be sufficiently expected.

  From this result, it can be concluded that the slit width is preferably set to about 30 to 60% of the slot width.

  FIG. 9 is a diagram for explaining an optimum method for punching a split core from a steel plate. When punching the split core, the rolled steel plate is rolled, and the split core is continuously punched from the rolled steel plate. At this time, the direction of the teeth of the split core is the rolling direction of the steel plate roll. It is preferable to perform punching so as to be (L direction).

  In general, magnetic steel sheets have the best magnetic properties in the rolling direction, and considering that the loss of the stator occurs mainly in the teeth, the direction with the best magnetic properties is taken as the teeth direction, so Loss can be minimized.

  FIG. 10 shows a split stator composed of split cores punched so that the longitudinal direction of the teeth is the rolling direction (L direction), and the longitudinal direction of the teeth is the direction (C direction) perpendicular to the rolling direction. A split stator composed of a punched core is prepared, and the total loss of both is compared.

  FIG. 10 shows that the loss when the longitudinal direction of the teeth is the L direction is reduced to about 85 with respect to the loss 100 when the longitudinal direction of the teeth is the C direction.

  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.

(A) is the perspective view which showed one Embodiment of the division | segmentation stator of this invention, (b) is the perspective view which expanded the small division | segmentation core. It is the perspective view which showed other embodiment of the division | segmentation stator of this invention. It is the perspective view which expanded two adjacent division | segmentation cores. It is the arrow view seen from the IV direction of FIG. It is the analysis result which compared the stress which arises in each split core connection part of the split stator (comparative example 1) which consists of a conventional split core, and the split stator (Example 1) of this invention shown in FIG. It is the analysis result which compared the loss resulting from the stress which arises in each split core connection part of the split stator (comparative example 1) which consists of a conventional split core, and the split stator (Example 1) of this invention shown in FIG. It is the analysis result which compared the loss by the transition magnetic flux of the division | segmentation stator (Example 1) of this invention shown in FIG. 1 and the division | segmentation stator (Example 2) of this invention shown in FIG. It is a graph for demonstrating the optimal range of ratio of a slit width and a slot width. It is the figure explaining one Embodiment of the method of punching a split core from a steel plate. It is the analysis result which compared the loss by the difference in the method of punching a split core from a steel plate. It is the perspective view which showed the conventional division | segmentation stator. FIG. 12 is a diagram illustrating a situation in which an eddy current caused by a leakage magnetic flux is generated at the end of the split core in the split stator of FIG. 11.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Electromagnetic steel plate, 2 ... Slit, 2a ... 1st slit, 2b ... 2nd slit, 10 ... Small division | segmentation core, 20 ... Cylindrical body, 100, 100A ... Division | segmentation stator

Claims (7)

A stator comprising an annular yoke and a plurality of teeth projecting radially inward from the yoke, wherein the stator core forming the stator is formed by a plurality of divided cores divided in the circumferential direction In the stator,
The side surfaces of both yokes where the adjacent divided cores face each other are provided with recesses and projections alternately in the height direction of the split cores, and the recesses and projections of both split cores are fitted together. A split stator in which an annular stator core is formed. The divided core is formed by laminating small divided cores having the same yoke width in the circumferential direction in the height direction of the divided core,
The split stator according to claim 1, wherein the plurality of small split cores are alternately stacked in the stacking direction, whereby the concave portion and the convex portion are formed on a side surface of the yoke of the split core.   The split stator according to claim 1, wherein a slit extending between adjacent split cores is formed in the yoke along the height direction of the split stator. In the yoke, a slit extending between adjacent divided cores is formed across the height direction of the divided stator,
In a posture in which a plurality of small divided cores are stacked, a slit provided on a side surface forming a convex portion of each small divided core is defined as a first divided slit, and provided on a side surface forming a concave portion on the opposite side. When the slit is the second divided slit, the first divided slit length is relatively longer than the second divided slit length, and the first divided slit is fitted in the posture in which the divided cores are fitted together. The split stator according to claim 2, wherein a slit straddling between the adjacent split cores is formed by communication between the split slit and the second split slit.   W2 / W1 is in the range of 0.3 to 0.6 when the slot width formed between adjacent teeth is W1 and the slit width between adjacent divided cores is W2. The split stator according to claim 3 or 4.   The split stator according to any one of claims 1 to 5, wherein the split core or the small split core is formed of a steel plate laminate in which steel plates are stacked.   A motor comprising the split stator according to claim 1.

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